Sunday, September 27, 2009
Why do I need a Transfer Switch?
A generator transfer switch is needed for individuals who wish to use an electric generator as a source of backup power for a home or business. The automatic transfer switch will switch the power source from the commercial power supply company to the onsite generator. These switches make it possible to limit the electricity from the electric company to be used only when the switch is in the proper position.
Automatic Transfer switches are the only recognized safe alternative for connecting an electrical load to the generator for an entire house or business. Putting an electric generator into the system without any kind of switch limiting its use could prove to be disastrous to the generator itself and to everything that is powered by it.
With hundreds of Transfer Switches in stock, we can provide the ideal switch with your generator purchase.
for more info...
1000kW Diesel Generators and up
We can provide a wide variety of options for control panels, load banks, voltage selector switches, water jacket heaters, silencers, multiple mainline circuit breakers, paint colors, cooling systems, annunciation, fuel tanks, and many other options.
We also offer custom walk in enclosures, remote fill stations, day tanks, remote radiators and many other options not available with off the shelf manufacturers.
No one in the industry can match Bowers ability to customize and engineer generator sets to a customer’s specific requirement.
Baldor manufactured - Mitsubishi Industrial powered diesel generator 1000kW Available in three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
1000kW Cummins Powered diesel generators Available in three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
Baldor manufactured - Mitsubishi Industrial powered diesel generator 1250kW Available in three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
Baldor manufactured - Mitsubishi Industrial powered diesel generator 1600kW Available in three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
Baldor manufactured - Mitsubishi Industrial powered diesel generator 2000kW Available in three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
151 to 200 kW Diesel Generators
John Deere diesel generator 150kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
John Deere diesel generator 180kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
John Deere diesel generator 200kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
200kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
more........
100 to 150 kW Diesel Generators
Cummins and John Deere industrial diesel engines power our product in the 100 and 150kW range. Both manufacturers offer engines meeting the most stringent EPA regulations.
For standby or prime power generation, John Deere and Cummins have the reliability and durability power managers count on for critical applications.
Find out why thousands of facilities depend on generator sets powered by John Deere engines. They are quick starting, clean running, fuel efficient and globally supported. This gives customers worry free service in times when power is most needed. They also offer more kW per cylinder to provide installation flexibility. With a record like that, it's easy to see why so many generator set manufacturers keep the lights on with John Deere and Cummins Engines.
John Deere diesel generator 100kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
105kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 150kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure orSound Attenuation (Super Silent) Models
150kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
For standby or prime power generation, John Deere and Cummins have the reliability and durability power managers count on for critical applications.
Find out why thousands of facilities depend on generator sets powered by John Deere engines. They are quick starting, clean running, fuel efficient and globally supported. This gives customers worry free service in times when power is most needed. They also offer more kW per cylinder to provide installation flexibility. With a record like that, it's easy to see why so many generator set manufacturers keep the lights on with John Deere and Cummins Engines.
John Deere diesel generator 100kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models
105kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 150kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure orSound Attenuation (Super Silent) Models
150kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
61 to 99 kW Diesel Generators
Our diesel generator sets are available in sizes ranging from 8 kW to 2 MW. These clean, modern diesels with optional exhaust after treatment are suitable for either standby/emergency power, continuous or prime power applications.
Generator sets include a prime mover fueled by diesel and an alternator that provides power at 50Hz or 60Hz, depending on the application. Our generator sets are the result of integrated design and manufacturing intended to meet your requirements for reliability, power quality, rated performance and efficient operation. In this size range we offer you either Cummins or John Deere powered generator sets. Service and parts support throughout the US and Canada.
65kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
75kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 80kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models also available.
for more info
Generator sets include a prime mover fueled by diesel and an alternator that provides power at 50Hz or 60Hz, depending on the application. Our generator sets are the result of integrated design and manufacturing intended to meet your requirements for reliability, power quality, rated performance and efficient operation. In this size range we offer you either Cummins or John Deere powered generator sets. Service and parts support throughout the US and Canada.
65kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
75kW Cummins Powered diesel generators Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 80kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models also available.
for more info
Light Tower Generators
Our mobile light tower provides 4000 watts of light anywhere you need it: Job site, road construction, emergency lighting or mining applications. With metal-halide lamps these light towers will provide light coverage for over 7 acres. Each model is powered by a Baldor 6000 watt light tower generator, which provides up to 2000 watts of reliable onsite power!. These light towers are powered by the dependable Kubota diesel engine. A huge 50-gallon fuel tank provides for 100-hours of operation.
Features:
• 4 powerful 1000-Watt metal halide lamps. Lamps are supported on both ends to enhance durability and long life.
• Elliptical light fixtures—provides a more efficient light pattern than conventional round fixtures.
• Operator has extra 2000 watts to run jobsite equipment. Control panel includes one 120-volt GFI and one 240-volt twist-lock receptacle.
• Enclosure constructed with heavy gauge painted aluminum. Padlockable door latches and integral forklift pockets included.
• Zinc plated 30’ 4-section mast with coiled mast cords. Strategically positioned winch allows the telescoping tower to be erected from a standing position.
• Tower rotates 360 degrees.
• Quiet, dependable Kubota diesel engine provides “flicker-free” operation.
• Tongue weight of 155 lbs. (with full load of fuel) allows one person to conveniently move unit around any jobsite.
• 50-gallon fuel tank included for up to 100 hours of running time.
• Quality highway trailer suspension.
• Low oil/high temperature shutdown protection and runtime hour indicator included.
• Battery included.
more info
Rental Grade Generators
We offer Baldor and Magnum in this section of our product offering. Our towable or mobile generators are designed and engineered for industrial, commercial and rental applications that require quiet operation, optimum performance and superior reliability. From the ultra quiet sound attenuated enclosures to the state-of-the-art electronics and controls, these units are engineered to meet the most rugged conditions. Place the unit at the job site, connect the load and start it up. Towable generators can also be used with an automatic transfer switch for standby applications.
We offer trailer mounted diesel generators
From two of the world's top diesel generator manufacturers. These are similar in configuration to Multiquip, Ingersoll Rand or Atlas Copco towable or portable diesel generators.
These towable diesel generators are designed and engineered for industrial, commercial and rental applications that require quiet operation, optimum performance and superior reliability.
We offer ultra quiet sound attenuated enclosures to the state-of-the-art electronics and controls, these units are engineered to meet the most rugged conditions. Place the unit at the job site, connect the load and start it up. Units can also be used with an automatic transfer switch for standby applications.
These trailer mounted or rental type generators are available from 25kVA/20kW to 400kVA/320kW these diesel units have a three position voltage selection switch for 1 and 3 phase connections; large integral diesel fuel tank; diesel fuel water separators and many safety features including water temperature shutdown, and low oil shutdown.
Detailed
31 to 60 kW Diesel Generators
In the 31 to 60kW Diesel Generators range we offer our customer a choice of three of the world’s top engine manufacturers – John Deere, Kubota and Lister Petter.
Our diesel generators in this size range feature:
•Industrial diesel engines that meet the latest EPA emission levels
•Brushless synchronous alternators with dynamic balancing and four pole construction
•Fully featured microprocessor based controller that’s easy to use and field programmable for customized installations
•All our generators are prototype tested and production tested to ensure the highest quality product
•Heavy duty construction that is designed and rated for either prime power or standby applications
•Backed by a world wide network of parts and service support centers
•Optional UL2200 (John Deere only) and NFPA 110 rating
•Optional weather resistant sound attenuated (super quiet) enclosures
•A full range of factory installed options are available
Lister Petter diesel generator 32kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Kubota diesel generator 40kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 40kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 50kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 60kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure or Sound Attenuation (Super Silent) Models also available.
for more info....
3 to 30 kW Diesel Generators
3 to 30 kW Diesel Generators
In the 3 to 30kW Diesel Generators we offer the highest quality products with an extensive US parts and service support network. We refuse to offer lower quality Chinese built products that are built to look like US made product, but don’t’ offer components with parts and service support in the US.
In our 3 to 6 kW Diesel Generators we offer Baldor exclusively - Baldo portable genertors are equipped with industrial grade engines to provide the performance and dependability you can count on.Baldor manufactures its own generators and backs them with an industry leading 3- year limited warranty.Baldor portable generators also feature "Switch less Full Pow'R", eliminating the need for a "Full Power" switch. Automatically get the 120V or 240V nameplate power rating without having to flip a switch. Baldor Premier portable generators incorporate the features you’ve come to expect from the leader in portable power generation.
Our premium brand in the 8-32kW Diesel Generators size is the “Lister Petter” brand - Lister Petter is our highest quality engine manufacturer. The Lister-Petter generator products are our recommendation for "off grid" or "prime power" applications where the generator is run eight to ten hours per day, 365 days a year. The Lister Petter brand began producing the highest quality diesel engines in England during the 1870’s. The Lister engine has been used to power; Caterpillar, Onan, FG Wilson and most other high quality generator manufacturer’s products. In the 1980’s Lister began producing their own brand of generators built for the most demanding applications.
In these severe duty applications fuel economy, reliability and engine life are the critical factors customer use in selecting their generator. The Lister product excels at all of these! When comparing fuel economy with other products - you will find that the Lister engine is at least ten percent more fuel efficient than it's competitors. Lister Petter time between overhaul is at least 30% longer than its competition and often as long as 40,000 hours.
We also offer Kubota powered diesel generators built to Bowers Generator Systems specifications. These generators offer rugged Kubota Industrial engines, 12 lead reconnectable generator ends, Aluminum enclosures built to withstand harsh marine environments with salt spray without rust damage!
When you compare our products in this size range – they come standard with features that are optional with our competition
•base mounted fuel tank – normally sized for 12 hour run time
•vibration isolators between engine/generator and base frame
•battery, battery rack and cables
•circuit breaker to protect the generator from overload
•two wire auto start ready controls (Automatic Transfer Switch required for true auto operation)
•fully automatic shutdown or alarm systems to protect your engine and generator
◦low oil pressure
◦high coolant temp
◦over speed (diesel engine run away)
◦and over crank
3.0 kW Baldor DG3E Hatz (German) Diesel Portable Generators Rope Start model - rugged durable fuel economy -a favorite with our US Marine Corps Customers - Optional Wheel Kit available
6.0 kW Baldor Elect Start Hatz (German) Diesel Portable Generator Electric Start with Rope Start backup model - rugged durable fuel economy - a favorite with our US Marine Corps Customers - Wheel Kit available
Lister Petter diesel generator 8kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Kubota diesel generator 12kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure Aluminum Sound Attenuation (Super Silent) Models also available.
Lister Petter diesel generator 12kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Kubota diesel generator 15kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available
SDMO diesel generator 16kW Single Phase - options include open models for indoor mounting and weather resistant sound attenuated enclosure of Powder Coated Steel.
SDMO diesel generator 16kW Three Phase - options include open models for indoor mounting and weather resistant sound attenuated enclosure of Powder Coated Steel.
Lister Petter diesel generator 17kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Kubota diesel generator 20kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
Lister Petter diesel generator 20kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Lister Petter diesel generator 26kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of either Aluminum or Powder Coated Steel. Sound Attenuation (Super Silent) Models also available.
Kubota diesel generator 30kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
John Deere diesel generator 30kW Available in either single phase or three phase, options include open models for indoor mounting, weather resistant enclosure of Aluminum Sound Attenuation (Super Silent) Models also available.
for more info....
Bowers Powers Diesel Generators
Bowers Powers offers diesel generators from 3 to 2000kW. We can "parallel" our larger generators to achieve 12mW. We offer the higest quality products with an extensive US parts and service support network. Our desiel power generators come standard with base mounted fuel tank, vibration isolators between engine/generator and base frame, battery, battery rack and cables, circuit breaker to protect the generator from overload and two wire auto start ready controls (Automatic Transfer Switch required for true auto operation). Our diesel generators come standard with fully automatic shutdown systems to protect your generator from low oil pressure, high coolant temp, over speed and over crank. You can have these built to your exact requirements - we offer an extensive array of options to set up the diesel generator to your requirements AND we have the sales engineering staff to assist you with selecting the best product for your unique installation!
Diesel Generators and Electric Generators
Genset Central We have over 60 years experience in supplying diesel generators and electric generators for industrial military and residential generator power requirements. If you are looking for a diesel generator or electric generator look no futher. We supply standby emergency power diesel generators, Kubota generators, gaseous generators, construction portable and mobile generators, diesel fuel tanks, ASCO transfer switches, manual transfer switches, Lister Petter generators, mobile light towers, agricultural generators, switchable voltage generators, RV and commercial compact diesel and gas generators, container generators, electrical generator ends for AC and DC applications, tactical quiet super quiet generators, commercial and residential super silent, trailer mounted construction generators, power modules, electrical transformers, switch gear, parallel equipment, mobile generators, generator controllers, Lister Petter generator and Cummins generators
We can assist you in selecting the product for any application. From the 8kW generator for your summer cabin generator to your backup power generator 2800KW industrial for your plant - we can help!! Our sales engineers each have a minimum of ten years experiences! We offer all electric generator accessories for residential and emergency gensets, standby generators industrial generators, portable, trailer or mobile generators, long run generator fuel tanks, battery chargers and automatic transfer switches.
Generators Types and Features
We recommend diesel due to their longevity and lower operating costs;
1. 1800 rpm water cooled diesel operate on average 20-30,000 hours before major engine maintenance is required.
2. 1800 rpm water cooled gas normally operate 6-10,000 hours because they are built on a lighter duty gasoline engine block.
3. 3600 rpm air-cooled gas engines are normally replaced – not overhauled at 500 to 1500 hours.
Because gas engines burn hotter (higher btu of the fuel), you will see significantly shorter lives. Our gensets are from the world’s top manufacturers. We offer products for high-end residential customers with larger homes to industrial and military customers seeking prime power or critical emergency backup generators.
Electric equipment is designed to use power with a fixed frequency: 60 Hertz (Hz) in the United States and Canada, 50 Hertz in Europe and Australia. The frequency output depends upon a fixed engine speed. To produce 60 Hz electricity, most diesel engines operate at 1800 or 3600 RPM. Each speed has its advantages and drawbacks. At 1800 RPM, four pole electric power sets are the most common and least expensive. They offer the best balance of noise, efficiency, cost, and engine life. At 3600 RPM, two pole generators are smaller and lightweight; they are best suited for portable, light-duty applications. In simple terms it’s like operating your car at 90 mph, versus 45mph — at 45mph your car will last longer; it is quieter, requires less maintenance, and has a longer life. Most 3600 rpm gensets are twin cylinder air-cooled lawn mower engines, while the water cooled 1800 rpm units are comparable to those found in diesel forklift and diesel tractor engines. The 1800 rpm water cooled engine will last longe r, offerless maintenance problems, and be more fuel efficient. We recommend diesel! Gensetcentral Systems can provide for all your backup power needs from 2 Mega Watt generator for industrial, residential and military applications. We can provide you with high quality gensets. We offer only top quality products that are priced at or below our competition who offer lesser brands Our diesel products are powered by world class diesel engines - we feature SDMO, Lister Petter, Katolight, Baldor, Kubota, John Deere and Cummins power plants
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Monday, September 7, 2009
Measuring Building Electrical Load Using a Stopwatch
If you intend on powering most of the items fed by your utility electric meter you can measure your total building load at any time using simply a stop watch while observing your meter. Follow the steps below to make this measurement.
First locate the electric meter which feeds your building. To use this method, it must be a traditional style kilowatthour meter with a rotating disk. The meters shown here are typical for small to medium residential services.
Next, read the constant on the face of the nameplate shown as Kh. This value is the number of watt-hours equivalent to one rotation of the disk.
Now, start the desired appliances, heating or air conditioning for the condition to be measured.
Using a stopwatch while watching for the black mark on the meter's disk, measure the time it takes for one or more disk rotations. If the disk is rotating rapidly, better accuracy will be attained if you time more than one rotation.
Finally, take the three values and use the equation below to calculate the watts seen by the electric meter.
Here is an example calculation for the first meter above. From the meter's face, Kh = 7.2. The time measured for 5 rotations of the disk was 24 seconds. Thus, Rev = 5 and T = 24 seconds. Solving for the electrical demand we have:
This is within the capability of common portable generators.
Note that this method is not practical for measuring the peak in-rush watts needed to start most loads because the transient happens so fast. Typical acceleration times for most motor loads are less than 1 second. Unless the response time of your eye and your thumb is extremely fast, you won't be able to measure these starting wattages without special recording instrumentation. For a sample of these measurements, see Test Reports below. .
Test Reports
This section contains test results and measurements for various electrical loads. Note that these measurements are representative only for the specific models shown and under the particular test conditions. Different conditions can alter both the current values and starting times.
Slightly different line voltages will affect results as will the wire size and length feeding the load. Ambient temperatures and thermostat settings will affect refrigeration compressor current demands. For well pumps, the pressure settings and the depth that the pump is positioned will affect measured results.
Refrigerator Starting Current
Refrigerator Starting Current
This test measured the starting current for a refrigerator with the following nameplate data.
Voltage 115 V AC
Frequency 60 Hz
Amps 5.0
Mfr. Date 3 / 86
Results of one measurement are shown in the plot below. It shows a maximum inrush current of about 13 amps which lasts only about one-half second. Also, the running current is significantly less than the nameplate value. It should be noted that most refrigerators (including this one) are "frost free." This means that on a regular basis a timer shuts off the compressor and turns on resistance heaters to clear frost buildup in the freezer section. This defrost current was not measured and is probably greater than the compressor running current. This may explain the large difference between the nameplate current value and the measured value.
Freezer Starting Current
This test measured the starting current for a freezer with the following nameplate data.
Voltage 115 V AC
Frequency 60 Hz
Amps 5.0
Mfr. Date early to mid 1970s
Results of one measurement are shown in the plot below. It shows a maximum inrush current of less than 5 amps which lasts only about 0.3 seconds. Also, the running current is significantly less than the nameplate value. It should be noted that most freezers are "frost free." However, this one is not.
Well Pump Starting Current
are shown in the plot below. It shows a maximum inrush current of about 18 amps which lasts only about 0.2 seconds.
Typical Running and Starting Loads
The graph below shows typical values for common residential loads. For applications that are approaching generator ratings, the actual nameplate load data, or better yet measured data, should be used to ensure an adequately sized unit.
CALCULATE ANY LOAD OR YOUR TOTAL LOAD - DOING IT EXACTLY
Instead of using this precise method of calculating loads you can use values "off of face plates" on equipment or the values shown on the Wattage Guide.
If you have no name plate data or the device is not listed on the Wattage Guide the follow the instructions here to determine the full load or device load.
For calculating full loads follow the procedures shown below. If you have an amp meter and you know how to use it, you can run the load and use a meter to determine the Running Load Requirements.
Picking the right size generator to meet your needs is not that complicated. There are several electrical parameters you need to be concerned with to make a proper selection.
Voltage Requirements
Most appliances operate on 120 volts. In spite of this, most electrical services for homes and small businesses are made up of a dual 120 volt feed, more commonly referred to as 120/240 volt. This type of feed allows the connection of those larger 240 volt electrical loads such as kitchen ranges, clothes dryers, well pumps, water heaters, heat pumps and central air conditioners. If you ever expect to have to power any 240 volt load, you should select a generator with 120 and 240 volt output. Also, if you intend on connecting the generator to the home or building at the 120/240 volt electric panel you should select a 120/240 volt model. Only in the case of separately powering individual 120 volt appliances should you consider a generator without 240 volt capability.
Running Load Requirements
Running load requirements are simply a total of all the loads to be operated simultaneously. This can be based on actual measurements if a clamp-on probe type ac current meter is available. If the building has a traditional style disk type kilowatt-hour meter an alternative is to use a stop watch and count rotations of the disk when the loads of interest are operating. See the procedure outlined below. Otherwise, an estimate of the total running load can be made by adding up the running wattages of all items to be powered at one time. Some appliances may not list the wattage on the nameplate, but may show the rated current in amps and voltage. The wattage can estimated from these two figures by multiplying them together to get the watts. See formula below:
watts = volts x amps
(for reactive loads this actually over estimates the watts slightly)
An estimate can also be obtained by using the bar chart further below.
Starting Load Requirements
Determining the starting requirements can be a bit more complicated. Certain electrical devices require additional power and current when initially turned on. This is true for motors because the rotor of the motor and the shaft driven load (fan, pump, compressor, saw, etc.) is initially at a standstill. It requires more energy to accelerate these rotating parts to operating speed than it does to keep them rotating. Therefore, during the period of acceleration, the demand on the power supply is greater. To precisely evaluate the motor starting capability the detailed motor characteristics need to be known. However, a rule of thumb is usually sufficient. Most engine driven generators will start a motor with up to 1/5th the horsepower of the engine, if it is the first load connected. For example, a 2500 watt generator driven by a 5 horsepower engine will usually start up to a 1 horsepower motor. This assumes a common type of motor design with NEMA code G starting characteristics. This data can be found on the motor nameplate.
Power Quality & Distortion
Perfectly pure AC power is a sine wave for both the voltage and current. Resistive loads such as incandescent lights and heaters are linear loads since the current is always proportional to the voltage applied. Some types of generators and non-linear loads can alter this perfect sine wave. A non-linear electrical load does not have a linear relationship between the voltage applied and the current that flows into the load. Certain types of electronics, lighting ballasts, arc welders and other devices are non-linear. Welding generators due to their design and poorly designed generators may also produce a distorted AC wave. When a significant portion of the load on a generator (or any power source for that matter) is non-linear, all the loads fed by the source will see this distortion. A measure of this distortion is called THD, or total harmonic distortion. If the distortion is severe enough, motors and transformers will operate hotter. Over a long period of time this can cause a reduction in life. And some other sensitive electronic equipment may not operate. An specific example is uninterruptible power supply (UPS) systems powering computers or communications equipment. These types of devices cause some distortion of the AC wave and at the same time can be negatively affected by it. A UPS system powered by an inadequately sized backup generator may continue draining the internal battery rather than switching over to generator power and charging the battery.
To reduce chances for THD problems, the rule of thumb is to select a backup generator kW size at least three times the kW of non-linear loads to be powered. For example, if you have 2000 watts of computers fed by UPS systems and 1000 watts of incandescent lighting to be fed by a generator first total the power:
2000 W + 1000 W = 3000 W
Then compare the total with three times the non-linear load portion:
3 x 2000 W = 6000 W
The generator needs to be at least 6000 watts in accordance with this rule of thumb.
If you have no name plate data or the device is not listed on the Wattage Guide the follow the instructions here to determine the full load or device load.
For calculating full loads follow the procedures shown below. If you have an amp meter and you know how to use it, you can run the load and use a meter to determine the Running Load Requirements.
Picking the right size generator to meet your needs is not that complicated. There are several electrical parameters you need to be concerned with to make a proper selection.
Voltage Requirements
Most appliances operate on 120 volts. In spite of this, most electrical services for homes and small businesses are made up of a dual 120 volt feed, more commonly referred to as 120/240 volt. This type of feed allows the connection of those larger 240 volt electrical loads such as kitchen ranges, clothes dryers, well pumps, water heaters, heat pumps and central air conditioners. If you ever expect to have to power any 240 volt load, you should select a generator with 120 and 240 volt output. Also, if you intend on connecting the generator to the home or building at the 120/240 volt electric panel you should select a 120/240 volt model. Only in the case of separately powering individual 120 volt appliances should you consider a generator without 240 volt capability.
Running Load Requirements
Running load requirements are simply a total of all the loads to be operated simultaneously. This can be based on actual measurements if a clamp-on probe type ac current meter is available. If the building has a traditional style disk type kilowatt-hour meter an alternative is to use a stop watch and count rotations of the disk when the loads of interest are operating. See the procedure outlined below. Otherwise, an estimate of the total running load can be made by adding up the running wattages of all items to be powered at one time. Some appliances may not list the wattage on the nameplate, but may show the rated current in amps and voltage. The wattage can estimated from these two figures by multiplying them together to get the watts. See formula below:
watts = volts x amps
(for reactive loads this actually over estimates the watts slightly)
An estimate can also be obtained by using the bar chart further below.
Starting Load Requirements
Determining the starting requirements can be a bit more complicated. Certain electrical devices require additional power and current when initially turned on. This is true for motors because the rotor of the motor and the shaft driven load (fan, pump, compressor, saw, etc.) is initially at a standstill. It requires more energy to accelerate these rotating parts to operating speed than it does to keep them rotating. Therefore, during the period of acceleration, the demand on the power supply is greater. To precisely evaluate the motor starting capability the detailed motor characteristics need to be known. However, a rule of thumb is usually sufficient. Most engine driven generators will start a motor with up to 1/5th the horsepower of the engine, if it is the first load connected. For example, a 2500 watt generator driven by a 5 horsepower engine will usually start up to a 1 horsepower motor. This assumes a common type of motor design with NEMA code G starting characteristics. This data can be found on the motor nameplate.
Power Quality & Distortion
Perfectly pure AC power is a sine wave for both the voltage and current. Resistive loads such as incandescent lights and heaters are linear loads since the current is always proportional to the voltage applied. Some types of generators and non-linear loads can alter this perfect sine wave. A non-linear electrical load does not have a linear relationship between the voltage applied and the current that flows into the load. Certain types of electronics, lighting ballasts, arc welders and other devices are non-linear. Welding generators due to their design and poorly designed generators may also produce a distorted AC wave. When a significant portion of the load on a generator (or any power source for that matter) is non-linear, all the loads fed by the source will see this distortion. A measure of this distortion is called THD, or total harmonic distortion. If the distortion is severe enough, motors and transformers will operate hotter. Over a long period of time this can cause a reduction in life. And some other sensitive electronic equipment may not operate. An specific example is uninterruptible power supply (UPS) systems powering computers or communications equipment. These types of devices cause some distortion of the AC wave and at the same time can be negatively affected by it. A UPS system powered by an inadequately sized backup generator may continue draining the internal battery rather than switching over to generator power and charging the battery.
To reduce chances for THD problems, the rule of thumb is to select a backup generator kW size at least three times the kW of non-linear loads to be powered. For example, if you have 2000 watts of computers fed by UPS systems and 1000 watts of incandescent lighting to be fed by a generator first total the power:
2000 W + 1000 W = 3000 W
Then compare the total with three times the non-linear load portion:
3 x 2000 W = 6000 W
The generator needs to be at least 6000 watts in accordance with this rule of thumb.
LOAD CODE
Example: The data tag on our electric motor shows a code of L. Our motor is 1/3 Hp. An L code is 84 amps per Hp x 1/3 (motor Hp) = 28 amps to start the motor shown.
CODE AMPS PER HP TO START CODE AMPS PER HP TO START
A 26.0 L 83.3
B 29.5 M 93.3
C 33.3 N 104.0
D 37.4 P 116.6
E 41.6 R 133.3
F 46.6 S 149.9
G 52.4 T 166.6
H 59.0 U 186.6
J 66.6 V more than 186.6
Load Code
Code is a letter which represents Amps per Hp to start the motor.
Multiply CODE (amps) times Hp of motor to determine starting amps.
DATA TAG
Method 2 requires a visual inspection of the data tag supplied by the electric motor manufacturer. All electrical motors have a data tag attached to their bodies that give volts, amps, phase, cycles, hp, and sometimes a code.
Volts (V) - The volts must be either 120 (110-120) or 120/240. 120/240 means that the motor can be wired to operate on 120V or 240V. Typical generators are either 120V or 120/240V.
Amps (A) - Indicates the amps required to RUN the electric motor but doesn't consider STARTING or LOADED power requirements.
Phase (PH) - The most commonly used generators can power only single phase motors only.
Horsepower (HP) - Rating of how much work an electric motor can perform.
Code - This isn't always supplied on the data tag. It represents the maximum STARTING power required of the electric motor.
Cycles (Hz) - All of U.S. electric appliances run at 60 cycles per second.
Read the Motor Mfg. Tag
Volts
Amps
Phase
Hp
Code
Cycles
ESTIMATING CHART
Method 1 requires using the load wattage estimating chart. It gives two figures of watts needed to power various loads; Running and starting watts.
Add up all of the watts estimated for the loads / appliances / tools that you want to operate at the same time.
If the load is a reactive type, use the STARTING WATTS for your estimation.
Select a generator that is as large or larger than the total number estimated. Example: If you only want to run a refrigerator (2200 starting watts) and (2) 100 watt light bulbs (200 watts) - You would need a 2500 watt generator.
Wattage Estimating Chart
What are the loads?
Add up the total wattage of loads
Use the starting watts if the load is a reactive type
Select a generator
LOAD POWER REQUIREMENTS
Here are a few ways to determine power requirements for various loads that are expected to be powered by a typical generator.
Method 1, using estimating charts, can be used to get a general idea of the generator size.
Method 2, reading the motor data tag, is more accurate since the data tag information is provided by the motor manufacturer. Data tag information does not always show STARTING power requirements for REACTIVE type loads. See "CODE CHART" at the end of this page.
*Note: Data tag information can usually be found in the owners / operating manual as well.
Determine Load Requirements
Estimating Chart
Read data tags
REACTIVE LOADS
When determining the proper generator for REACTIVE type loads, you must consider three modes of operation:
STARTING - The electric motor requires more power to start. The starting power required can be THREE times the running amount.
RUNNING - The power required to run the electric motor after it has been started.
LOADED - When the electric motor begins to work (saw begins cutting wood), its power requirement will increase. This is not applicable for most household appliances.
Reactive Loads
Starting
Running
Loaded
RESISTIVE LOADS
The equation shows the relationship between watts, volts and amps in a PURELY RESISTIVE load. If you know any of the two variables, the third can be calculated.
Example: You want a generator to power a 1000 watt flood light. The light is 120V and requires 1000 watts of power. Using the equation, we can calculate that the floodlight will draw 8.3 amps of electrical current.
For REACTIVE loads, the equation shows only a general relationship between watts, volts and amps. That's because the power requirements for REACTIVE loads changes with operating conditions.
Resistive Loads
Watts = Volts x Amps
LOADS
In the previous example, the light bulbs are the LOAD of the generator. The EM2500 generator can handle a LOAD of no more than 2500 watts maximum.
The light bulb example is called a RESISTIVE type load and the POWER it requires is pretty easy to understand. Other RESISTIVE types of LOAD are things like toasters, convection ovens, hot plates, curling irons, coffee makers, stereos and TV's. RESISTIVE LOADS are usually those that do not have electric motors.
Another load is the REACTIVE type and is a little more confusing. Typically, a REACTIVE load contains an electric motor. This type of load may require up to three times as much power (wattage) to START as it does to keep it running. Examples of REACTIVE type loads are air conditioners, refrigerators / freezers, furnace fans, well pumps, bench grinders and air compressors.
Loads
Resistive
Reactive
MAXIMUM AND RATED POWER
A generator should never be operated at its MAXIMUM power output for more than 30 minutes.
RATED power is a more reliable measure of generator power. It is the power that a generator can produce for long periods of time. Typically the RATED power is 90% of the MAXIMUM power.
Rated and Maximum
Model number = maximum . output in watts.
Maximum power for 1/2 hour.
Rated is usually 10% less.
GENERATOR POWER
Most generators produce AC voltage, very similar to the voltage available in your home.
The amount of power that a generator can produce is rated in watts (power).
For Example, an EM2500 generator produces a MAXIMUM 2500 watts of power. This means the EM2500 could provide power to 25 one hundred watt light bulbs at the same time. The generator would then be at its MAXIMUM power output.
Generator Power
Model = Power
Power = Watts
GENERATOR USAGE
Generators are used to perform a wide variety of chores. The wide variety of generators meet the demands of the variety of almost all potential users. Generators offered by GeneratorJoe provide a high quality power source that is reliable and convenient to use.
Generator Usage
Homeowner - Stand-by
Recreation - Boating - Camping
Commercial - Industrial - . Construction - .Rental
Understanding Loads & Sizing
This page explains how to determine loads so that you can size your generator for your needs. Normally you want to power the "essential" things and leave some room for other uses.
You must always remember that the generator cannot run at full load for long periods. Always assume that you will need more items powered rather then less and leave a margin of safety above and beyond the continuous load of the generator you select.
It is less expensive to buy more power (higher wattage) in one unit then to buy a second unit or "upgrade" by trading in your old generator for a new one. Often installation costs for a larger unit is a fraction more initially but if you have to upsize your connection afterwards its very expensive.
All these require common sense judgment and some experience. Ask your electrician for advise, he can help you decide what you need.
Below is a short tutorial which will help you understand the basics. The Wattage Guide will provide you with values for the most common items at home and on the job. If you can get nameplate data your calculations will be more accurate, however using the Guide will be sufficient in most cases, especially if you leave yourself plenty of growing room. Make sure you have plenty of size by getting generator big enough for now and the future.
Go to Calculations to use your new understanding and apply the numbers you gathered. You should be able to determine the right size generator for you.
You must always remember that the generator cannot run at full load for long periods. Always assume that you will need more items powered rather then less and leave a margin of safety above and beyond the continuous load of the generator you select.
It is less expensive to buy more power (higher wattage) in one unit then to buy a second unit or "upgrade" by trading in your old generator for a new one. Often installation costs for a larger unit is a fraction more initially but if you have to upsize your connection afterwards its very expensive.
All these require common sense judgment and some experience. Ask your electrician for advise, he can help you decide what you need.
Below is a short tutorial which will help you understand the basics. The Wattage Guide will provide you with values for the most common items at home and on the job. If you can get nameplate data your calculations will be more accurate, however using the Guide will be sufficient in most cases, especially if you leave yourself plenty of growing room. Make sure you have plenty of size by getting generator big enough for now and the future.
Go to Calculations to use your new understanding and apply the numbers you gathered. You should be able to determine the right size generator for you.
look Meadowfield GenPower
Meadowfield GenPower Ltd can provide you with a comprehensive product line of modern diesel powered generator sets. they have sets available from 10kva to 500kva and can source larger units if required. they can assess and match your specific needs.
they specialise in diesel powered gensets and provide their clients with first class service based on old style customer orientated values. With the emphasis being on quality of services and commitment to ongoing customer satisfaction.
Gensets can be supplied in all weather acoustic, super silent or skid mounted form. Equipped with Automatic Mains Failure. Fuel storage is internal, but bunded bulk fuel tanks can be supplied for long non-attended operational periods.
Full installation services can be supplied, or the customer can do this in-house if preferred.
for more info
Friday, September 4, 2009
GENERATOR FUEL - WHAT GENERATOR FUEL IS BEST?
There are many advantages and disadvantages to different types of fuel. Nearly all Generators use either gasoline, diesel, natural gas or propane. The following information will hopefully answer any questions or concerns you may have concerning different fuel sources. Some general features of the generator itself influence purchase decision. Where possible we indicted hardware and environmental differences in generator set types. You should consider all the factors shown. POSITIVE, NEGATIVE, GENERATOR FACTORS, are shown by the color of the features.
Gasoline: Advantages:
Common fuel source - easily obtained
Increases portability of smaller generators
Disadvantages:
Highly flammable
Short shelf life of fuel (approximately 12 months)
Storing large quantities of fuel is hazardous
May not be available during power outages
Somewhat expensive fuel, check your local prices
Inefficient
Diesel: Advantages:
Least flammable fuel source
Fuel easily obtained (fuel is easier to obtain during a disaster because it is a necessary fuel for the military, trucking industry, and farming operations)
On site fuel delivery available
Engine life for liquid-cooled 1800 RPM engines can approach 20,000 hours if properly serviced depending on the application and environment.
High speed 3600 RPM diesel engines normally have a 10,000 to 15,000 hour life expectancy with proper maintenance and service under most conditions
Less expensive to operate. The general rule of thumb for fuel consumption is 7% of the rated generator output (Example: 20 kW x 7% = 1.4 gallon per hour at full load).
Designed for off-road applications and can operate on dyed or farm/construction diesel fuel which is sold without the road tax and thus is considerably cheaper to purchase.
Engines designed to work under a load for long periods of time and perform better when worked hard rather than operated under light loads.
Can operate in sub-artic conditions with fuel additive.
Equipment is competitively priced for a comparative sized water-cooled gaseous models with the same features.
In high use situations overall long term cost of operation is much lower than gaseous GenSets.
Diesel Fuel Use Chart
Disadvantages:
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages.
Diesel fuel storage must be considered relative to required run time in your geographical area. If you live in hurricane country you might need a large fuel tank due to the high possibility of extended power outages
Engine noise is higher on a diesel compared to a gaseous engine. Use of a properly designed enclosure and sound attenuation system is more critical on a diesel engine system.
Subject to "wet stacking" or over fueling if run for long periods of time with ultra light loads (less than 40% of the rated output). "Wet Stacking" causes the engine to smoke and run rough because the injectors become carbonized. Running a heavy load will usually clean up the over-fuel condition and allow the engine to perform normally. Diesel engines operate better and are more fuel efficient when loaded (70-80% is optimum).
In sensitive emission areas in some states diesel engines are prohibited from operating over a prescribed number of hours per year to help reduce pollution levels
Requires clean moisture free fuel and a bit more maintenance than a comparable gaseous unit;
Some cities and counties require the generator on-board fuel tanks to be double-wall containment type which can increase the cost of the generator system.
Typically heavier and require more planning to load and unload than a lightweight gaseous GenSet.
Bio-Diesel: Advantages: (Same as Diesel see above)
Least flammable fuel source
Easily obtained
On site fuel delivery available
Bio-Diesel is a cleaner-burning diesel replacement fuel made from natural, renewable sources such as new and used vegetable oils and animal fats. Like petroleum diesel, Bio-Diesel operates in compression-ignition engines. Blends of up to 20% Bio-Diesel (mixed with petroleum diesel fuels) can be used in nearly all diesel equipment and are compatible with most storage and distribution equipment. These low level blends (20% and less) don't require any engine modifications and can provide the same payload capacity as diesel. Using Bio-Diesel in a conventional diesel engine substantially reduces emissions.
Disadvantages: (Same as Diesel see above)
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages
Obtaining oils and other fuels.
Mixing and maintaining proper percentage of oils/fuel
Emulsified Diesel: Advantages: (Same as Diesel see above)
Least flammable fuel source
Easily obtained
On site fuel delivery available
This is diesel that is mixed with a small percentage of water and an agent that keeps the water and diesel mixed. By adding the water to the diesel a smaller amount emissions are created when the fuel is burned.
Disadvantages: (Same as Diesel see above)
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages
Obtaining oils and other fuels
Mixing and maintaining proper percentage of water/fuel
Propane:*
*See propane notes below.
Advantages:
Long shelf life
Clean burning
Easily stored in both large tanks or in smaller 5 - 10 gallon cylinders
Obtainable during power outages - gas stations may be unable to pump fuel during an area wide outage
Home delivery available for larger tanks
Quieter engine noise level
More emission compliant
Gaseous engines do not have a problem with "wet stacking like diesels
Less expensive units with air-cooled engines are budget priced.
Engine life for liquid-cooled 1800 RPM engines can approach 5,000 to 6,000 hours on industrial quality gaseous GenSets
Disadvantages:
Pressurized cylinder of flammable gas
Fuel system is more complicated (increased possibility of failure)
Larger tanks are not aesthetically pleasing (unsightly)
Fuel system plumbing results in higher installation cost
Somewhat expensive fuel, check your local prices
Propane can become very dangerous if lines are broken.
Propane begins to derate around -20 degrees above zero
Initial cost of generator is somewhat higher, 15 to 20% especially in sizes larger than 30 kW.
More expensive to operate by as much as 3-times the fuel consumption compared to diesels;
Shorter life expectancy by a factor or 10 to 1for air-cooled models and 3 to 1 for water-cooled models compared to diesel powered GenSets
Smaller air-cooled gaseous engines are less expensive than comparable diesels but have a short life expectancy as low as 500-hours depending on engine make and use
Shorter life than diesel engines
Natural Gas:
Advantages:
Unlimited fuel source - refueling not necessary
Clean burning
More available during power outage.
Quieter engine noise level
More emission compliant
More convenient fuel source (natural gas)
Gaseous engines do not have a problem with "wet stacking like diesels
less expensive units with air-cooled engines are budget priced.
Natural gas is a mixture of hydrocarbons (mainly methane (CH4)) and is produced either from gas wells or in conjunction with crude oil production. Because of the gaseous nature of this fuel, it must be stored onboard a vehicle in either a compressed gaseous state (CNG) or more commonly as liquefied state (LNG).
Disadvantages:
May be unavailable during natural disasters (earthquakes, etc)
Lower power output (30% less BTU's per unit than gasoline.
Fuel system plumbing results in higher installation cost.
Fuel not available in many areas.
Natural gas (NG) begins to derate at +20 degrees above zero.
Initial cost of generator is somewhat higher, 15 to 20% especially in sizes larger than 30 kW.
More expensive to operate by as much as 3-times the fuel consumption compared to diesels;
Shorter life expectancy by a factor or 10 to 1for air-cooled models and 3 to 1 for water-cooled models compared to diesel powered GenSets
Smaller air-cooled gaseous engines are less expensive than comparable diesels but have a short life expectancy as low as 500-hours depending on engine make and use.
Hurricanes and earthquakes can disrupt the flow of natural gas lines with up-rooted trees
Natural Gas can become very dangerous if lines are broken.
Gasoline: Advantages:
Common fuel source - easily obtained
Increases portability of smaller generators
Disadvantages:
Highly flammable
Short shelf life of fuel (approximately 12 months)
Storing large quantities of fuel is hazardous
May not be available during power outages
Somewhat expensive fuel, check your local prices
Inefficient
Diesel: Advantages:
Least flammable fuel source
Fuel easily obtained (fuel is easier to obtain during a disaster because it is a necessary fuel for the military, trucking industry, and farming operations)
On site fuel delivery available
Engine life for liquid-cooled 1800 RPM engines can approach 20,000 hours if properly serviced depending on the application and environment.
High speed 3600 RPM diesel engines normally have a 10,000 to 15,000 hour life expectancy with proper maintenance and service under most conditions
Less expensive to operate. The general rule of thumb for fuel consumption is 7% of the rated generator output (Example: 20 kW x 7% = 1.4 gallon per hour at full load).
Designed for off-road applications and can operate on dyed or farm/construction diesel fuel which is sold without the road tax and thus is considerably cheaper to purchase.
Engines designed to work under a load for long periods of time and perform better when worked hard rather than operated under light loads.
Can operate in sub-artic conditions with fuel additive.
Equipment is competitively priced for a comparative sized water-cooled gaseous models with the same features.
In high use situations overall long term cost of operation is much lower than gaseous GenSets.
Diesel Fuel Use Chart
Disadvantages:
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages.
Diesel fuel storage must be considered relative to required run time in your geographical area. If you live in hurricane country you might need a large fuel tank due to the high possibility of extended power outages
Engine noise is higher on a diesel compared to a gaseous engine. Use of a properly designed enclosure and sound attenuation system is more critical on a diesel engine system.
Subject to "wet stacking" or over fueling if run for long periods of time with ultra light loads (less than 40% of the rated output). "Wet Stacking" causes the engine to smoke and run rough because the injectors become carbonized. Running a heavy load will usually clean up the over-fuel condition and allow the engine to perform normally. Diesel engines operate better and are more fuel efficient when loaded (70-80% is optimum).
In sensitive emission areas in some states diesel engines are prohibited from operating over a prescribed number of hours per year to help reduce pollution levels
Requires clean moisture free fuel and a bit more maintenance than a comparable gaseous unit;
Some cities and counties require the generator on-board fuel tanks to be double-wall containment type which can increase the cost of the generator system.
Typically heavier and require more planning to load and unload than a lightweight gaseous GenSet.
Bio-Diesel: Advantages: (Same as Diesel see above)
Least flammable fuel source
Easily obtained
On site fuel delivery available
Bio-Diesel is a cleaner-burning diesel replacement fuel made from natural, renewable sources such as new and used vegetable oils and animal fats. Like petroleum diesel, Bio-Diesel operates in compression-ignition engines. Blends of up to 20% Bio-Diesel (mixed with petroleum diesel fuels) can be used in nearly all diesel equipment and are compatible with most storage and distribution equipment. These low level blends (20% and less) don't require any engine modifications and can provide the same payload capacity as diesel. Using Bio-Diesel in a conventional diesel engine substantially reduces emissions.
Disadvantages: (Same as Diesel see above)
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages
Obtaining oils and other fuels.
Mixing and maintaining proper percentage of oils/fuel
Emulsified Diesel: Advantages: (Same as Diesel see above)
Least flammable fuel source
Easily obtained
On site fuel delivery available
This is diesel that is mixed with a small percentage of water and an agent that keeps the water and diesel mixed. By adding the water to the diesel a smaller amount emissions are created when the fuel is burned.
Disadvantages: (Same as Diesel see above)
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages
Obtaining oils and other fuels
Mixing and maintaining proper percentage of water/fuel
Propane:*
*See propane notes below.
Advantages:
Long shelf life
Clean burning
Easily stored in both large tanks or in smaller 5 - 10 gallon cylinders
Obtainable during power outages - gas stations may be unable to pump fuel during an area wide outage
Home delivery available for larger tanks
Quieter engine noise level
More emission compliant
Gaseous engines do not have a problem with "wet stacking like diesels
Less expensive units with air-cooled engines are budget priced.
Engine life for liquid-cooled 1800 RPM engines can approach 5,000 to 6,000 hours on industrial quality gaseous GenSets
Disadvantages:
Pressurized cylinder of flammable gas
Fuel system is more complicated (increased possibility of failure)
Larger tanks are not aesthetically pleasing (unsightly)
Fuel system plumbing results in higher installation cost
Somewhat expensive fuel, check your local prices
Propane can become very dangerous if lines are broken.
Propane begins to derate around -20 degrees above zero
Initial cost of generator is somewhat higher, 15 to 20% especially in sizes larger than 30 kW.
More expensive to operate by as much as 3-times the fuel consumption compared to diesels;
Shorter life expectancy by a factor or 10 to 1for air-cooled models and 3 to 1 for water-cooled models compared to diesel powered GenSets
Smaller air-cooled gaseous engines are less expensive than comparable diesels but have a short life expectancy as low as 500-hours depending on engine make and use
Shorter life than diesel engines
Natural Gas:
Advantages:
Unlimited fuel source - refueling not necessary
Clean burning
More available during power outage.
Quieter engine noise level
More emission compliant
More convenient fuel source (natural gas)
Gaseous engines do not have a problem with "wet stacking like diesels
less expensive units with air-cooled engines are budget priced.
Natural gas is a mixture of hydrocarbons (mainly methane (CH4)) and is produced either from gas wells or in conjunction with crude oil production. Because of the gaseous nature of this fuel, it must be stored onboard a vehicle in either a compressed gaseous state (CNG) or more commonly as liquefied state (LNG).
Disadvantages:
May be unavailable during natural disasters (earthquakes, etc)
Lower power output (30% less BTU's per unit than gasoline.
Fuel system plumbing results in higher installation cost.
Fuel not available in many areas.
Natural gas (NG) begins to derate at +20 degrees above zero.
Initial cost of generator is somewhat higher, 15 to 20% especially in sizes larger than 30 kW.
More expensive to operate by as much as 3-times the fuel consumption compared to diesels;
Shorter life expectancy by a factor or 10 to 1for air-cooled models and 3 to 1 for water-cooled models compared to diesel powered GenSets
Smaller air-cooled gaseous engines are less expensive than comparable diesels but have a short life expectancy as low as 500-hours depending on engine make and use.
Hurricanes and earthquakes can disrupt the flow of natural gas lines with up-rooted trees
Natural Gas can become very dangerous if lines are broken.
INDUSTRIAL DIESEL ENGINE TYPES AND APPLICATIONS
What is a Diesel Engine?
The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine. The fuel in a diesel engine is ignited by suddenly exposing it to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition energy (such as a spark plug). This process is known as the diesel cycle after Rudolf Diesel, who invented it in 1892. While traditional diesel engine generators may not fit into our definition of 'alternative energy' sources, they are still a valuable addition to a remote power or grid back-up system.
Types of Diesel Engines
There are two classes of diesel engines: two-stroke and four-stroke. Most diesel engines generally use the four-stroke cycle, with some larger engines operating on the two-stroke cycle. Normally, banks of cylinders are used in multiples of two, though any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration.
Generator sets produce either single or three phase power. Most homeowners require single phase whereas industrial or commercial applications usually require three phase power. Diesel engine generators are recommended due to their longevity and lower operating costs. Modern diesel engines are quiet and generally require much less maintenance than comparably sized gas (natural gas or propane) units.
Diesel Engine Generators - Commercial/Industrial Applications
Diesel generators are designed to meet the needs of small and medium-sized businesses apart from heavy usage in industries. A generator is a revolutionary product that brings clean and affordable standby power within the reach of millions of enterprises, homes and small businesses. Reducing the cost of backup power and making generators easy to install is becoming the norm these days.
Businesses lose money when they shut down during a blackout. Considering the impact of significant revenue loss, the economics of investing in standby power is compelling. To illustrate the point: If a retail business averages $1000 an hour at the cash register, the loss of revenue during an extended outage will be very high, not to mention the cost of having employees idle during that time. However, diesel powered generators eliminate the risk of a blackout. Add the advantages of being open while competitors without backup power are shut down and the cost / benefit analysis looks even better. Investing in generators is a simple way to safeguard revenue, maintain security, avoid losses, and protect the bottom line.
Most modern generators are engineered to meet emergency power needs. These units continuously monitor the electrical current and automatically start up if power is interrupted and shut off when utility service is returned. In industries, during critical processes, generators can supply emergency power to all vital and selected loads as desired. This quality leads to widespread use of diesel-powered generators across recreational, residential, commercial, communication, and industrial applications. Today, most state-of-the-art- hospitals, five star hotels, business process outsourcing centers, manufacturing plants, telecommunications organizations, commercial buildings, data centers, emergency facilities, large industries, and mining companies require uninterrupted power and have backup diesel engine generators.
On the Road:
The vast majority of modern heavy road vehicles like trucks and buses, ships, long-distance trains, large-scale portable power generators, and most farm and mining vehicles have diesel engines. However, in some countries they are not nearly as popular in passenger vehicles as they are heavier, noisier, have performance characteristics that make them slower to accelerate. In general, they are also more expensive than petrol vehicles. Modern diesel engines have come a long way and with Turbo Direct Injection systems now in vehicles, one would be hard-pressed to notice a difference between diesel and gasoline engines.
In some countries, where tax rates make diesel fuel much cheaper than petrol, diesel vehicles are very popular. Newer designs have significantly narrowed differences between petrol and diesel vehicles in these areas. The BMW diesel lab in Austria is considered to be the worldwide leader in the development of automotive diesel engines. After a long spell with relatively few diesel cars in its lineup, Mercedes Benz has returned to diesel-powered cars in the 21st century with an emphasis on high performance.
In the agricultural field, tractors, irrigation pumps and threshing machines and other equipment are predominantly diesel powered. Construction is another sector that relies heavily on diesel power. All concrete pavers, scrapers, rollers, trenchers and excavators run on diesel.
In the Sky:
A few airplanes have been using diesel engines since the late 1930s. The newer automotive diesel engines have power-weight ratios comparable to the ancient spark-ignition designs and have far superior fuel efficiency. Their use of electronic ignition, fuel injection, and sophisticated engine management systems also makes them far easier to operate than mass-produced spark-ignition aircraft engines. The cost of diesel fuel compared to petrol has led to considerable interest in diesel-powered small general aviation planes, and several manufacturers have recently begun selling diesel engines for this purpose.
On Water:
High-speed engines are used to power tractors, trucks, yachts, buses, cars, compressors, generators and pumps. The largest diesel engines are used to power ships and liners along the high seas. These huge engines have power outputs up to 90,000 kW, turn at about 60 to 100 rpm, and are 15 meters tall.
Underground:
The mining and mineral extraction sector worldwide relies heavily on diesel power to harness natural resources such as aggregates, precious metals, iron ore, oil, gas, and coal. Diesel-powered shovels and drills excavate these products and load them into enormous mining trucks or onto conveyer belts that also operate on the same fuel. Overall, diesel accounts for 72 percent of the energy used by the mining sector.
Both surface and underground mining operations rely on diesel-powered equipment to extract materials and load trucks. The largest rubber-tired, diesel-powered equipment used in mining are enormous off-road trucks with engines of over 2,500 horsepower, capable of hauling over 300 tons per load. These giant trucks trundling across the land are a sight to behold.
In Hospitals
Emergency backup generators are a must have for any major medical healthcare facilities. Due to the critical nature of the work these facilities do and the position their patients are in, power failures are simply not an option. For many years, both military and public hospitals have relied on industrial strength generator sets to take over whenever the power goes out, whether it's from a local outage or major natural disaster like a hurricane or flood.
Behind Datacenters
Computers are at the heart of today's industry. When servers and systems go down, communications can be lost, business stops, data is lost, workers sit idle, and just about everything comes to a halt. It is for that reason that almost all communications and telecommunications companies of all shapes turn to diesel generators as their primary backup power option. With the reliability of their services affecting so many people, they really have no choice but to have a solid backup power option in place for both their business, and the customers they serve.
Summary
Diesel is used in most industrial sectors overwhelmingly because it provides more power per unit of fuel and its lower volatility makes it safer to handle. One really exciting prospect of diesel over petrol is the possibility of eliminating petroleum consumption entirely. Most diesel engines can be coaxed into burning vegetable oil instead of diesel and all of them can burn various processed forms of vegetable oil without loss in life or efficiency.
The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine. The fuel in a diesel engine is ignited by suddenly exposing it to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition energy (such as a spark plug). This process is known as the diesel cycle after Rudolf Diesel, who invented it in 1892. While traditional diesel engine generators may not fit into our definition of 'alternative energy' sources, they are still a valuable addition to a remote power or grid back-up system.
Types of Diesel Engines
There are two classes of diesel engines: two-stroke and four-stroke. Most diesel engines generally use the four-stroke cycle, with some larger engines operating on the two-stroke cycle. Normally, banks of cylinders are used in multiples of two, though any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration.
Generator sets produce either single or three phase power. Most homeowners require single phase whereas industrial or commercial applications usually require three phase power. Diesel engine generators are recommended due to their longevity and lower operating costs. Modern diesel engines are quiet and generally require much less maintenance than comparably sized gas (natural gas or propane) units.
Diesel Engine Generators - Commercial/Industrial Applications
Diesel generators are designed to meet the needs of small and medium-sized businesses apart from heavy usage in industries. A generator is a revolutionary product that brings clean and affordable standby power within the reach of millions of enterprises, homes and small businesses. Reducing the cost of backup power and making generators easy to install is becoming the norm these days.
Businesses lose money when they shut down during a blackout. Considering the impact of significant revenue loss, the economics of investing in standby power is compelling. To illustrate the point: If a retail business averages $1000 an hour at the cash register, the loss of revenue during an extended outage will be very high, not to mention the cost of having employees idle during that time. However, diesel powered generators eliminate the risk of a blackout. Add the advantages of being open while competitors without backup power are shut down and the cost / benefit analysis looks even better. Investing in generators is a simple way to safeguard revenue, maintain security, avoid losses, and protect the bottom line.
Most modern generators are engineered to meet emergency power needs. These units continuously monitor the electrical current and automatically start up if power is interrupted and shut off when utility service is returned. In industries, during critical processes, generators can supply emergency power to all vital and selected loads as desired. This quality leads to widespread use of diesel-powered generators across recreational, residential, commercial, communication, and industrial applications. Today, most state-of-the-art- hospitals, five star hotels, business process outsourcing centers, manufacturing plants, telecommunications organizations, commercial buildings, data centers, emergency facilities, large industries, and mining companies require uninterrupted power and have backup diesel engine generators.
On the Road:
The vast majority of modern heavy road vehicles like trucks and buses, ships, long-distance trains, large-scale portable power generators, and most farm and mining vehicles have diesel engines. However, in some countries they are not nearly as popular in passenger vehicles as they are heavier, noisier, have performance characteristics that make them slower to accelerate. In general, they are also more expensive than petrol vehicles. Modern diesel engines have come a long way and with Turbo Direct Injection systems now in vehicles, one would be hard-pressed to notice a difference between diesel and gasoline engines.
In some countries, where tax rates make diesel fuel much cheaper than petrol, diesel vehicles are very popular. Newer designs have significantly narrowed differences between petrol and diesel vehicles in these areas. The BMW diesel lab in Austria is considered to be the worldwide leader in the development of automotive diesel engines. After a long spell with relatively few diesel cars in its lineup, Mercedes Benz has returned to diesel-powered cars in the 21st century with an emphasis on high performance.
In the agricultural field, tractors, irrigation pumps and threshing machines and other equipment are predominantly diesel powered. Construction is another sector that relies heavily on diesel power. All concrete pavers, scrapers, rollers, trenchers and excavators run on diesel.
In the Sky:
A few airplanes have been using diesel engines since the late 1930s. The newer automotive diesel engines have power-weight ratios comparable to the ancient spark-ignition designs and have far superior fuel efficiency. Their use of electronic ignition, fuel injection, and sophisticated engine management systems also makes them far easier to operate than mass-produced spark-ignition aircraft engines. The cost of diesel fuel compared to petrol has led to considerable interest in diesel-powered small general aviation planes, and several manufacturers have recently begun selling diesel engines for this purpose.
On Water:
High-speed engines are used to power tractors, trucks, yachts, buses, cars, compressors, generators and pumps. The largest diesel engines are used to power ships and liners along the high seas. These huge engines have power outputs up to 90,000 kW, turn at about 60 to 100 rpm, and are 15 meters tall.
Underground:
The mining and mineral extraction sector worldwide relies heavily on diesel power to harness natural resources such as aggregates, precious metals, iron ore, oil, gas, and coal. Diesel-powered shovels and drills excavate these products and load them into enormous mining trucks or onto conveyer belts that also operate on the same fuel. Overall, diesel accounts for 72 percent of the energy used by the mining sector.
Both surface and underground mining operations rely on diesel-powered equipment to extract materials and load trucks. The largest rubber-tired, diesel-powered equipment used in mining are enormous off-road trucks with engines of over 2,500 horsepower, capable of hauling over 300 tons per load. These giant trucks trundling across the land are a sight to behold.
In Hospitals
Emergency backup generators are a must have for any major medical healthcare facilities. Due to the critical nature of the work these facilities do and the position their patients are in, power failures are simply not an option. For many years, both military and public hospitals have relied on industrial strength generator sets to take over whenever the power goes out, whether it's from a local outage or major natural disaster like a hurricane or flood.
Behind Datacenters
Computers are at the heart of today's industry. When servers and systems go down, communications can be lost, business stops, data is lost, workers sit idle, and just about everything comes to a halt. It is for that reason that almost all communications and telecommunications companies of all shapes turn to diesel generators as their primary backup power option. With the reliability of their services affecting so many people, they really have no choice but to have a solid backup power option in place for both their business, and the customers they serve.
Summary
Diesel is used in most industrial sectors overwhelmingly because it provides more power per unit of fuel and its lower volatility makes it safer to handle. One really exciting prospect of diesel over petrol is the possibility of eliminating petroleum consumption entirely. Most diesel engines can be coaxed into burning vegetable oil instead of diesel and all of them can burn various processed forms of vegetable oil without loss in life or efficiency.
Tuesday, September 1, 2009
DIESEL FUELED GENERATORS - A RECOMMENDATION
Diesel engine generators the best choice for your generator needs for longevity & efficiency.
Why is diesel a better choice for your generator application?
We recommend diesels due to their:
a) Longevity - Think of all the18 wheeler trucks capable of 1,000,000 miles of operation before major service. Most trucks are diesel powered.
b) Lower fuel costs - Diesel uses less fuel consumption per kilowatt (kW) produced).
c) Lower maintenance costs - diesel have fewer parts. no spark system, more rugged and more reliable engine.
Today’s modern diesels are quiet and normally require less maintenance than comparably sized gas (natural gas or propane) units. Overall operating costs are typically thirty to fifty percent less than gasoline units.
Diesel engines running at 1800 RPM and water cooled operate on average for 12,000 to 30,000 hours before major maintenance is required. Gasoline engines running at 1800 RPM and water cooled gas units normally operate on average for 6,000 to10,000 hours because they are built using lighter duty gasoline engine blocks.
Gasoline engines running at 3600 rpm and air cooled are normally replaced – not overhauled at 500 to 1500 hours.
Gasoline units run hotter due to the higher BTU rating of the fuel, you will therefore see significantly shorter gasoline engine life. Diesels run cooler and last longer.
DIFFERENCES BETWEEN GASOLINE AND DIESEL ENGINES
Fuel Gasoline Diesel
Fuel
Ignition
Gasoline
Takes a mixture of gas and air, compresses it and ignites the mixture with a spark.
Diesel
Takes in just air, compresses it and then injects fuel into the compressed air. The heat of the compressed air lights the fuel spontaneously.
Fuel
Compression
Gasoline
Compresses at a ratio of 8:1 to 12:1
Diesel
Compresses at a ratio of 14:1 to as high as 25:1. The higher compression ratio of the diesel engine leads to better efficiency.
Fuel
Fuel Provision
Gasoline
Uses either carburetion, in which the air and fuel is mixed long before the air enters the cylinder, or port fuel injection, in which the fuel is injected just prior to the intake stroke (outside the cylinder).
Diesel
Uses direct fuel injection -- the diesel fuel is injected directly into the cylinder. The diesel engine has no spark plug, that it intakes air and compresses it and that it then injects the fuel directly into the combustion chamber (direct injection). It is the heat of the compressed air that lights the fuel in a diesel engine.
Fuel
Injection Process
Gasoline
Most car engines use port injection or a carburetor rather than direct injection. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine -- if it compresses the air too much, the fuel/air mixture spontaneously ignites and causes knocking.
Diesel
Diesels compress only air, so the compression ratio can be much higher. The higher the compression ratio, the more power is generated.
Fuel
Injector Engineering
Gasoline
Fuel injected gasoline engines is more refined and less problematic then diesel engines because the fuel is easier to ignite.
Diesel
The injector on a diesel engine is its most complex component and has been the subject of a great deal of experimentation -- in any particular engine it may be located in a variety of places. The injector has to be able to withstand the temperature and pressure inside the cylinder and still deliver the fuel in a fine mist. Getting the mist circulated in the cylinder so that it is evenly distributed is also a problem, so some diesel engines employ special induction valves, pre-combustion chambers or other devices to swirl the air in the combustion chamber or otherwise improve the ignition and combustion process.
Fuel
Starting Process
Gasoline
Smaller engines and engines that do not have such advanced computer controls use glow plugs to solve the cold-starting problem
Diesel
When a diesel engine is cold, the compression process may not raise the air to a high enough temperature to ignite the fuel. The glow plug is an electrically heated wire (think of the hot wires you see in a toaster) that helps ignite the fuel when the engine is cold so that the engine can start.
____________________________
In today's world, where fuel prices are increasing as a consequence of spiraling demand and diminishing supply, you need to choose a cost effective fuel to meet your needs. Thanks to the invention of Rudolph Diesel, the diesel engine has proved to be extremely efficient and cost effective. Diesel fuel is priced moderately higher than gasoline but diesel has a higher energy density, i.e. more energy can be extracted from diesel as compared with the same volume of gasoline. Diesel engines in automobiles provide higher mileage, making it an obvious choice for heavy-duty transportation and equipment. Diesel is heavier and oilier compared with gasoline, and has a boiling point higher than that of water. Diesel engines are attracting greater attention due to higher efficiency and cost effectiveness.
How Does a Diesel Engine Work?
The distinction lies in the type of ignition. While gasoline engines operate on spark ignition, diesel engines employ compression - ignition for igniting the fuel. In the latter, air is drawn into the engine and subjected to high compression that heats it up. This results in a very high temperature in the engine, much higher than the temperature attained in a gasoline engine. At peak temperature and pressure, diesel that is let into the engine ignites on account of the extreme temperature.
In a diesel engine air and the fuel are infused into the engine at different stages, as opposed to a gas engine where a mixture of air and gas are introduced. Fuel is injected into the diesel engine using an injector whereas in a gasoline engine, a carburetor is used for this purpose. In a gasoline engine, fuel and air are sent into the engine together, and then compressed. The air and fuel mixture limits fuel compression, and hence the overall efficiency. A diesel engine compresses only air, and the ratio can be much higher. A diesel engine compresses at the ratio of 14:1 up to 25:1, whereas in a gasoline engine the compression ratio is between 8:1 and 12:1. After combustion, the combustion by-products are removed from the engine through the exhaust. For starting during cold months extra heat is provided through 'glow plugs'.
Diesel engines can either be two cycle or four cycle and are chosen depending on mode of operation. Air-cooled and liquid-cooled engines are the variants to be chosen appropriately. It is preferable to use a liquid-cooled generator as it is quiet in operation and has evenly controlled temperature.
Advantages of a Diesel Engine
The diesel engine is much more efficient and preferable as compared with gasoline engine due to the following reasons:
Modern diesel engines have overcome disadvantages of earlier models of higher noise and maintenance costs. They are now quiet and require less maintenance as compared with gas engines of similar size.
They are more rugged and reliable.
There is no sparking as the fuel auto-ignites. The absence of spark plugs or spark wires lowers maintenance costs.
Fuel cost per Kilo Watt (kW) produced is thirty to fifty percent lower than that of gas engines.
An 1800 rpm water cooled diesel unit operates for 12,000 to 30,000 hours before any major maintenance is necessary. An 1800 rpm water cooled gasoline unit usually operates for 6000-10,000 hours before it needs servicing.
Gas units burn hotter than diesel units, and hence they have a significantly shorter life compared with diesel units.
Applications & Uses for Diesel Engines
Diesel engines are commonly used as mechanical engines, power generators and in mobile drives. They find wide spread use in locomotives, construction equipment, automobiles, and countless industrial applications. Their realm extends to almost all industries and can be observed on a daily basis if you were to look under the hood of everything you pass by. Industrial diesel engines and diesel powered generators have construction, marine, mining, hospital, forestry, telecommunications, underground, and agricultural applications, just to name a few. Power generation for prime or standby backup power is the major application of today's diesel generators. Check out our article on the various types of engines and generators and their common applications for more examples.
Power Generators
Diesel powered generators, or electrical generator sets, are used in countless industrial and commercial establishments. The generators can be used for small loads, such as in homes, as well as for larger loads like industrial plants, hospitals, and commercial buildings. They can either be prime power sources or standby/back-up power sources. They are available in various specifications and sizes. Diesel generator sets rating 5-30KW are typically used in simple home and personal applications like recreational vehicles. Industrial applications cover a wider spectrum of power ratings (from 30 kW to 6 Megawatts) and are used in numerous industries throughout the globe. For home use, single-phase power generators are sufficient. Three-phase power generators are primarily used for industrial purposes.
Why is diesel a better choice for your generator application?
We recommend diesels due to their:
a) Longevity - Think of all the18 wheeler trucks capable of 1,000,000 miles of operation before major service. Most trucks are diesel powered.
b) Lower fuel costs - Diesel uses less fuel consumption per kilowatt (kW) produced).
c) Lower maintenance costs - diesel have fewer parts. no spark system, more rugged and more reliable engine.
Today’s modern diesels are quiet and normally require less maintenance than comparably sized gas (natural gas or propane) units. Overall operating costs are typically thirty to fifty percent less than gasoline units.
Diesel engines running at 1800 RPM and water cooled operate on average for 12,000 to 30,000 hours before major maintenance is required. Gasoline engines running at 1800 RPM and water cooled gas units normally operate on average for 6,000 to10,000 hours because they are built using lighter duty gasoline engine blocks.
Gasoline engines running at 3600 rpm and air cooled are normally replaced – not overhauled at 500 to 1500 hours.
Gasoline units run hotter due to the higher BTU rating of the fuel, you will therefore see significantly shorter gasoline engine life. Diesels run cooler and last longer.
DIFFERENCES BETWEEN GASOLINE AND DIESEL ENGINES
Fuel Gasoline Diesel
Fuel
Ignition
Gasoline
Takes a mixture of gas and air, compresses it and ignites the mixture with a spark.
Diesel
Takes in just air, compresses it and then injects fuel into the compressed air. The heat of the compressed air lights the fuel spontaneously.
Fuel
Compression
Gasoline
Compresses at a ratio of 8:1 to 12:1
Diesel
Compresses at a ratio of 14:1 to as high as 25:1. The higher compression ratio of the diesel engine leads to better efficiency.
Fuel
Fuel Provision
Gasoline
Uses either carburetion, in which the air and fuel is mixed long before the air enters the cylinder, or port fuel injection, in which the fuel is injected just prior to the intake stroke (outside the cylinder).
Diesel
Uses direct fuel injection -- the diesel fuel is injected directly into the cylinder. The diesel engine has no spark plug, that it intakes air and compresses it and that it then injects the fuel directly into the combustion chamber (direct injection). It is the heat of the compressed air that lights the fuel in a diesel engine.
Fuel
Injection Process
Gasoline
Most car engines use port injection or a carburetor rather than direct injection. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine -- if it compresses the air too much, the fuel/air mixture spontaneously ignites and causes knocking.
Diesel
Diesels compress only air, so the compression ratio can be much higher. The higher the compression ratio, the more power is generated.
Fuel
Injector Engineering
Gasoline
Fuel injected gasoline engines is more refined and less problematic then diesel engines because the fuel is easier to ignite.
Diesel
The injector on a diesel engine is its most complex component and has been the subject of a great deal of experimentation -- in any particular engine it may be located in a variety of places. The injector has to be able to withstand the temperature and pressure inside the cylinder and still deliver the fuel in a fine mist. Getting the mist circulated in the cylinder so that it is evenly distributed is also a problem, so some diesel engines employ special induction valves, pre-combustion chambers or other devices to swirl the air in the combustion chamber or otherwise improve the ignition and combustion process.
Fuel
Starting Process
Gasoline
Smaller engines and engines that do not have such advanced computer controls use glow plugs to solve the cold-starting problem
Diesel
When a diesel engine is cold, the compression process may not raise the air to a high enough temperature to ignite the fuel. The glow plug is an electrically heated wire (think of the hot wires you see in a toaster) that helps ignite the fuel when the engine is cold so that the engine can start.
____________________________
In today's world, where fuel prices are increasing as a consequence of spiraling demand and diminishing supply, you need to choose a cost effective fuel to meet your needs. Thanks to the invention of Rudolph Diesel, the diesel engine has proved to be extremely efficient and cost effective. Diesel fuel is priced moderately higher than gasoline but diesel has a higher energy density, i.e. more energy can be extracted from diesel as compared with the same volume of gasoline. Diesel engines in automobiles provide higher mileage, making it an obvious choice for heavy-duty transportation and equipment. Diesel is heavier and oilier compared with gasoline, and has a boiling point higher than that of water. Diesel engines are attracting greater attention due to higher efficiency and cost effectiveness.
How Does a Diesel Engine Work?
The distinction lies in the type of ignition. While gasoline engines operate on spark ignition, diesel engines employ compression - ignition for igniting the fuel. In the latter, air is drawn into the engine and subjected to high compression that heats it up. This results in a very high temperature in the engine, much higher than the temperature attained in a gasoline engine. At peak temperature and pressure, diesel that is let into the engine ignites on account of the extreme temperature.
In a diesel engine air and the fuel are infused into the engine at different stages, as opposed to a gas engine where a mixture of air and gas are introduced. Fuel is injected into the diesel engine using an injector whereas in a gasoline engine, a carburetor is used for this purpose. In a gasoline engine, fuel and air are sent into the engine together, and then compressed. The air and fuel mixture limits fuel compression, and hence the overall efficiency. A diesel engine compresses only air, and the ratio can be much higher. A diesel engine compresses at the ratio of 14:1 up to 25:1, whereas in a gasoline engine the compression ratio is between 8:1 and 12:1. After combustion, the combustion by-products are removed from the engine through the exhaust. For starting during cold months extra heat is provided through 'glow plugs'.
Diesel engines can either be two cycle or four cycle and are chosen depending on mode of operation. Air-cooled and liquid-cooled engines are the variants to be chosen appropriately. It is preferable to use a liquid-cooled generator as it is quiet in operation and has evenly controlled temperature.
Advantages of a Diesel Engine
The diesel engine is much more efficient and preferable as compared with gasoline engine due to the following reasons:
Modern diesel engines have overcome disadvantages of earlier models of higher noise and maintenance costs. They are now quiet and require less maintenance as compared with gas engines of similar size.
They are more rugged and reliable.
There is no sparking as the fuel auto-ignites. The absence of spark plugs or spark wires lowers maintenance costs.
Fuel cost per Kilo Watt (kW) produced is thirty to fifty percent lower than that of gas engines.
An 1800 rpm water cooled diesel unit operates for 12,000 to 30,000 hours before any major maintenance is necessary. An 1800 rpm water cooled gasoline unit usually operates for 6000-10,000 hours before it needs servicing.
Gas units burn hotter than diesel units, and hence they have a significantly shorter life compared with diesel units.
Applications & Uses for Diesel Engines
Diesel engines are commonly used as mechanical engines, power generators and in mobile drives. They find wide spread use in locomotives, construction equipment, automobiles, and countless industrial applications. Their realm extends to almost all industries and can be observed on a daily basis if you were to look under the hood of everything you pass by. Industrial diesel engines and diesel powered generators have construction, marine, mining, hospital, forestry, telecommunications, underground, and agricultural applications, just to name a few. Power generation for prime or standby backup power is the major application of today's diesel generators. Check out our article on the various types of engines and generators and their common applications for more examples.
Power Generators
Diesel powered generators, or electrical generator sets, are used in countless industrial and commercial establishments. The generators can be used for small loads, such as in homes, as well as for larger loads like industrial plants, hospitals, and commercial buildings. They can either be prime power sources or standby/back-up power sources. They are available in various specifications and sizes. Diesel generator sets rating 5-30KW are typically used in simple home and personal applications like recreational vehicles. Industrial applications cover a wider spectrum of power ratings (from 30 kW to 6 Megawatts) and are used in numerous industries throughout the globe. For home use, single-phase power generators are sufficient. Three-phase power generators are primarily used for industrial purposes.
Friday, August 28, 2009
Compare Convenience and Cost - Portable vs Stationary
Most people can not live comfortably without continuous, stable electrical power. Thousands of people purchase small electric generator sets to protect themselves, their families and their businesses in the likely event of power failures. Here are some basic tips.
Portable vs. Stationary – Let’s Compare Convenience and Cost
Although a portable generator can be manhandled, with an average weight of 250-300 lbs, you can't call them lightweight. If you purchase one, make sure it comes with a set of wheels (sometimes these are optional). Portables are universally fueled with gasoline, a fuel that requires safe storage and extra care in handling. Some portables have very small fuel tanks, so they need refueling every half hour or so. Given the choice, go for a portable generator with at least a 5 gal tank. And don’t forget that gasoline doesn’t store very well and will get gummy over time.
Portable generator owners usually employ a series of extension cords to connect the generator to specific items in their house, such as a refrigerator, lights, computer, and TV. Although this system works, it is most practical for outages of a short duration. Most portable generators are “rope started”, like lawnmowers. If your wife, teenager or elderly relative will be using the generator (not recommended) you should go for an electric start option, if available. As you can see, there is essentially nothing automatic about a portable generator.
On the other hand, a stationary (automatic) generator averages $5,972 - but look at the differences!
Stationary generators start at about 500 lbs and are designed with a weather protective housing that mounts outdoors on a level surface. Fuel is continuously supplied via your natural gas service or propane tank, whichever you choose. Your electrician will “hard wire” the electrical cables to your distribution panel (no extension cords to deal with here).
Starting is fully automatic. In fact, it can take just 15-30 seconds from the beginning of the power outage until the generator is completely up and running. This type of generator employs an automatic transfer switch which monitors the incoming power and switches the generator on and off as needed.
How do you know which size generator you need?
Determining the size of your generator is all important. Electric power is measured in watts and 1,000 watts is called a kilowatt. All electrical appliances in your home have an electrical tag or label on them, which states the wattage. Sometimes the tag shows only the voltage and amperage. If this is the case, multiply the voltage by the amperage to get the wattage. Example: say the electrical label on the back of your toaster reads 120 volts and 10 amps. To get the wattage, 120 V x 10 A = 1200 watts. Since 1000 watts = one kilowatt, the load can also be considered 1.2KW.
Add up the wattages of the loads that you consider essential, then multiply by 75% to account for the fact that everything will not be on at the same time. It’s a good idea to discuss your loads with an electrician - he can also determine or verify your loads easily and quickly using his ammeter.
Portable generators usually range from 3-15KW but you can only get 1/2 the power out of each large outlet unless the generator has a full power plug (which is rare). Stationary generators are in the 7-40KW or larger range. The larger sizes are normally needed only if you have heavy electrical loads like a large well pump or a central air conditioner. The average sized generator for a normal home (without a central air conditioner) is in the 10-12KW range.
Portable vs. Stationary – Let’s Compare Convenience and Cost
Although a portable generator can be manhandled, with an average weight of 250-300 lbs, you can't call them lightweight. If you purchase one, make sure it comes with a set of wheels (sometimes these are optional). Portables are universally fueled with gasoline, a fuel that requires safe storage and extra care in handling. Some portables have very small fuel tanks, so they need refueling every half hour or so. Given the choice, go for a portable generator with at least a 5 gal tank. And don’t forget that gasoline doesn’t store very well and will get gummy over time.
Portable generator owners usually employ a series of extension cords to connect the generator to specific items in their house, such as a refrigerator, lights, computer, and TV. Although this system works, it is most practical for outages of a short duration. Most portable generators are “rope started”, like lawnmowers. If your wife, teenager or elderly relative will be using the generator (not recommended) you should go for an electric start option, if available. As you can see, there is essentially nothing automatic about a portable generator.
On the other hand, a stationary (automatic) generator averages $5,972 - but look at the differences!
Stationary generators start at about 500 lbs and are designed with a weather protective housing that mounts outdoors on a level surface. Fuel is continuously supplied via your natural gas service or propane tank, whichever you choose. Your electrician will “hard wire” the electrical cables to your distribution panel (no extension cords to deal with here).
Starting is fully automatic. In fact, it can take just 15-30 seconds from the beginning of the power outage until the generator is completely up and running. This type of generator employs an automatic transfer switch which monitors the incoming power and switches the generator on and off as needed.
How do you know which size generator you need?
Determining the size of your generator is all important. Electric power is measured in watts and 1,000 watts is called a kilowatt. All electrical appliances in your home have an electrical tag or label on them, which states the wattage. Sometimes the tag shows only the voltage and amperage. If this is the case, multiply the voltage by the amperage to get the wattage. Example: say the electrical label on the back of your toaster reads 120 volts and 10 amps. To get the wattage, 120 V x 10 A = 1200 watts. Since 1000 watts = one kilowatt, the load can also be considered 1.2KW.
Add up the wattages of the loads that you consider essential, then multiply by 75% to account for the fact that everything will not be on at the same time. It’s a good idea to discuss your loads with an electrician - he can also determine or verify your loads easily and quickly using his ammeter.
Portable generators usually range from 3-15KW but you can only get 1/2 the power out of each large outlet unless the generator has a full power plug (which is rare). Stationary generators are in the 7-40KW or larger range. The larger sizes are normally needed only if you have heavy electrical loads like a large well pump or a central air conditioner. The average sized generator for a normal home (without a central air conditioner) is in the 10-12KW range.
COMPARISON OF PORTABLE AND STATIONARY GENERATORS FOR HOME STANDBY USE
is is a comparison of a 5,000 and 10,000 watt portable generator compared to a 12,000 watt Onan Residential Standby generator. We used our experience and costs based on Santa Rosa, CA. Not all areas of the country will be the same or have the same conditions.
Cost is only one factor. Carefully consider the safety, security, setup and storage issues shown on the chart. Please read the summary at the end of this chart too! Whether you agree or now we want you to be informed. No matter what you decide to purchase we would like to have your order.
We have residential generators from 8,000 watts (8 kW) to 45,000 watts (45 kW), in propane, natural gas and diesel. We have portable generators from 1,000 watts (1 kW) to 15,000 watts (15 kW) in gasoline, diesel, propane and natural gas. The majority of portable generators are gasoline powered.
We will be offering portable kits which include a generator, transfer switch, cord and outlet box for one low price. To see our kits click Portable Kits. COMING SOON!
If you are considering a portable for an RV use, see our chart at Portable vs RV. For more information about fuels see Generator Fuels.
COMPARISON OF CATEGORIES BETWEEN PORTABLE AND STATIONARY GENERATORS FOR HOME STANDBY USE
Category Typical Portable Stationary Winner
6,000 Watts 12,000 Watts Stationary
Models Portable vs Residential Winco WC6000HE Onan RS12000 Onan RS12000
Time of Need Usually at night, bad weather Must be protected from rain. In protected cabinet. Stationary
Powers % of House 50% 100% Stationary
Largest Single Load Due to plug restrictions 20 Amps 100 Amps Stationary
Remote Control/Start Automatic Preferred No Auto-start Auto-start Standard Stationary
Auto Choking Automatic Preferred No Auto-choke Auto-Choke Standard Stationary
Move In/Out Permanent Desirable Required unless shelter Move not required Stationary
Setup or Connecting Permanent Desirable Required unless shelter Always Connected Stationary
Transfer of Power Automatic Preferred Manual Only Automatic Stationary. Automatic
Unattended Operation Unattended desirable Short Periods Only Runs Unattended Stationary
Operation by Family Desirable Usually difficult Automatic Operation Stationary
Weather Protection Desirable Requires shelter or move out/in Enclosure Standard Stationary
Security Desirable Easy to steal if left out Anchored to ground Stationary
Security During Operation Highly Desirable Must go outside during storm to start and refuel Runs Automatically Stationary
Security Storage Highly Desirable Must keep inside and drain fuel Secure Outside Stationary
Fuel Tank Type Strongest Preferred Usually plastic Usually steel Stationary
Fuel Tank Size Larger better than smaller 4.5 gallons 50-100 gallons Stationary
Run Time per Tank Longer is better at 1/2 load 11.2 hours
at full load 5 hours 200 gallon tank lasts 40 hours Stationary
Refueling Automatic Preferred Every 5-11 hours @ 1/2 load Every 40 hours Stationary
Storage of Fuel Desirable, if safe Fuel cans outside,
not inside In Tank Outside Stationary
Fuel Economy @ Full Load Poor Excellent Stationary
Refueling System Automatic Preferred By hand with cans, stop generator By Fuel Supplier Stationary
Layout Simple is Preferred See Diagrams See Diagrams Stationary
Number of Parts Smallest number preferred 4, generator, switch, outlet, cord 2, generator & switch Stationary
Generator Cost Lower is better than higher $1,918 $4,202 Stationary
Transfer Switch Cost Lower is better than higher Gen-Tran 200600, Manual, $235 Onan Indoor, 100 Amp, Automatic, $670 Portable, Manual
Other Parts Outlet box, cords, plug Gen-Tran $125 Fuel Tank, $200 Stationary
Estimated Install Labor (electrician) Lower is better than higher $500 $900 Stationary
Total Initial Cost Lower is better than higher $2,778.00 $5,972, ($3,194 more) Portable
Cost Per Hour to Run @ 1/2 Load Lower is better than higher 0.53 gallons per hour or $1.50 hr 54 cu.ft/hr,
< $1.00 hour Stationary
Estimated Life Hours Longer is better than shorter 2,000 10,000 Stationary
Years of Life Longer is better than shorter 555 15 Stationary
Cost per year life years Lower is better than higher $574 $398 Stationary
Noise Lower is better than higher 79 db(A) <70 db(A) Stationary
Oil Capacity Larger better than smaller 1 Quart 3 quarts Stationary
Adds to value of home? According to RE appraiser No Yes 50% Minimum Stationary
Need Permit? According to City of Santa Rosa in California No Yes, $25 Portable
Even though the Portable is cheaper overall, by almost double in the 6,000 watt size and only $3,194 more in the 12,000 watt size; you have to ask yourself, is it worth the savings. I reality you only get 50 % of the power off a portable because you can only get the output from one plug which is 1/2 of the generators capacity unless there is a full power plug.
If you, (or your family members if you are out of town, sick or injured), must struggle one time to haul the portable out, plug it in and refuel it in foul weather at night every 4-11 hours, is it worth the difference in savings.
Read the list over a few times and you should conclude that unless you love to get cold and wet, stay up late and play survivor, your better off to have an installed system that is totally automatic.
REMEMBER: Cost is only one factor. Carefully consider the safety, security, setup and storage issues shown on the chart. Please read the summary at the enc of this chart as well. Whether you agree or now we want you to be informed. No matter what you decide to purchase we would like to have your order.
We have residential generators from 8,000 watts (8 kW) to 45,000 watts (45 kW), in propane, natural gas and diesel. We have portable generators from 1,000 watts (1 kW) to 15,000 watts (15 kW) in gasoline, diesel, propane and natural gas. The majority of portable generator are gasoline powered.
We will be offering portable kits which include a generator, transfer switch, cord and outlet box for one low price. To see our kits click Portable Kits. COMING SOON!
If you are considering a portable for an RV use, see our chart at Portable vs RV. For more information about fuels see Generator Fuels.
Cost is only one factor. Carefully consider the safety, security, setup and storage issues shown on the chart. Please read the summary at the end of this chart too! Whether you agree or now we want you to be informed. No matter what you decide to purchase we would like to have your order.
We have residential generators from 8,000 watts (8 kW) to 45,000 watts (45 kW), in propane, natural gas and diesel. We have portable generators from 1,000 watts (1 kW) to 15,000 watts (15 kW) in gasoline, diesel, propane and natural gas. The majority of portable generators are gasoline powered.
We will be offering portable kits which include a generator, transfer switch, cord and outlet box for one low price. To see our kits click Portable Kits. COMING SOON!
If you are considering a portable for an RV use, see our chart at Portable vs RV. For more information about fuels see Generator Fuels.
COMPARISON OF CATEGORIES BETWEEN PORTABLE AND STATIONARY GENERATORS FOR HOME STANDBY USE
Category Typical Portable Stationary Winner
6,000 Watts 12,000 Watts Stationary
Models Portable vs Residential Winco WC6000HE Onan RS12000 Onan RS12000
Time of Need Usually at night, bad weather Must be protected from rain. In protected cabinet. Stationary
Powers % of House 50% 100% Stationary
Largest Single Load Due to plug restrictions 20 Amps 100 Amps Stationary
Remote Control/Start Automatic Preferred No Auto-start Auto-start Standard Stationary
Auto Choking Automatic Preferred No Auto-choke Auto-Choke Standard Stationary
Move In/Out Permanent Desirable Required unless shelter Move not required Stationary
Setup or Connecting Permanent Desirable Required unless shelter Always Connected Stationary
Transfer of Power Automatic Preferred Manual Only Automatic Stationary. Automatic
Unattended Operation Unattended desirable Short Periods Only Runs Unattended Stationary
Operation by Family Desirable Usually difficult Automatic Operation Stationary
Weather Protection Desirable Requires shelter or move out/in Enclosure Standard Stationary
Security Desirable Easy to steal if left out Anchored to ground Stationary
Security During Operation Highly Desirable Must go outside during storm to start and refuel Runs Automatically Stationary
Security Storage Highly Desirable Must keep inside and drain fuel Secure Outside Stationary
Fuel Tank Type Strongest Preferred Usually plastic Usually steel Stationary
Fuel Tank Size Larger better than smaller 4.5 gallons 50-100 gallons Stationary
Run Time per Tank Longer is better at 1/2 load 11.2 hours
at full load 5 hours 200 gallon tank lasts 40 hours Stationary
Refueling Automatic Preferred Every 5-11 hours @ 1/2 load Every 40 hours Stationary
Storage of Fuel Desirable, if safe Fuel cans outside,
not inside In Tank Outside Stationary
Fuel Economy @ Full Load Poor Excellent Stationary
Refueling System Automatic Preferred By hand with cans, stop generator By Fuel Supplier Stationary
Layout Simple is Preferred See Diagrams See Diagrams Stationary
Number of Parts Smallest number preferred 4, generator, switch, outlet, cord 2, generator & switch Stationary
Generator Cost Lower is better than higher $1,918 $4,202 Stationary
Transfer Switch Cost Lower is better than higher Gen-Tran 200600, Manual, $235 Onan Indoor, 100 Amp, Automatic, $670 Portable, Manual
Other Parts Outlet box, cords, plug Gen-Tran $125 Fuel Tank, $200 Stationary
Estimated Install Labor (electrician) Lower is better than higher $500 $900 Stationary
Total Initial Cost Lower is better than higher $2,778.00 $5,972, ($3,194 more) Portable
Cost Per Hour to Run @ 1/2 Load Lower is better than higher 0.53 gallons per hour or $1.50 hr 54 cu.ft/hr,
< $1.00 hour Stationary
Estimated Life Hours Longer is better than shorter 2,000 10,000 Stationary
Years of Life Longer is better than shorter 555 15 Stationary
Cost per year life years Lower is better than higher $574 $398 Stationary
Noise Lower is better than higher 79 db(A) <70 db(A) Stationary
Oil Capacity Larger better than smaller 1 Quart 3 quarts Stationary
Adds to value of home? According to RE appraiser No Yes 50% Minimum Stationary
Need Permit? According to City of Santa Rosa in California No Yes, $25 Portable
Even though the Portable is cheaper overall, by almost double in the 6,000 watt size and only $3,194 more in the 12,000 watt size; you have to ask yourself, is it worth the savings. I reality you only get 50 % of the power off a portable because you can only get the output from one plug which is 1/2 of the generators capacity unless there is a full power plug.
If you, (or your family members if you are out of town, sick or injured), must struggle one time to haul the portable out, plug it in and refuel it in foul weather at night every 4-11 hours, is it worth the difference in savings.
Read the list over a few times and you should conclude that unless you love to get cold and wet, stay up late and play survivor, your better off to have an installed system that is totally automatic.
REMEMBER: Cost is only one factor. Carefully consider the safety, security, setup and storage issues shown on the chart. Please read the summary at the enc of this chart as well. Whether you agree or now we want you to be informed. No matter what you decide to purchase we would like to have your order.
We have residential generators from 8,000 watts (8 kW) to 45,000 watts (45 kW), in propane, natural gas and diesel. We have portable generators from 1,000 watts (1 kW) to 15,000 watts (15 kW) in gasoline, diesel, propane and natural gas. The majority of portable generator are gasoline powered.
We will be offering portable kits which include a generator, transfer switch, cord and outlet box for one low price. To see our kits click Portable Kits. COMING SOON!
If you are considering a portable for an RV use, see our chart at Portable vs RV. For more information about fuels see Generator Fuels.
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