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.
Friday, August 28, 2009
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.
TRANSFER SWITCHES
For safety's sake, hire a licensed electrician to install a transfer switch that distributes power from the generator to the home's circuit box. This reduces the need for multiple extension cords running from the generator to specific appliances, and eliminates the risk of electrical "back feed" injuring utility workers working on downed power lines.
The transfer switch (around $150 and up) is installed beside the main electrical panel, and then it's connected to circuits you'll need during a blackout. When the power goes out, you simply crank up the generator and run a single extension cord from it to the transfer switch. We sell transfer switches for small generators manufactured by Gen-Tran, to get more information, Just Click > Transfer Switches, Portable-Small Applications. For larger systems, Just Click > Transfer Switches, Large and Industrial.
Once the generator is running, you can choose which circuits you want to use by flipping the switches on the transfer switch.
It's important to keep track of what's being powered because the transfer switch is often wired into more circuits than the generator can handle all at once.
A typical transfer-switch installation will take less than two hours and cost around $100-$200, but it's an investment that will be fully appreciated the next time the power goes out.
Make your installation simple so all family members can use the generator safely. Make an instruction sheet and put it with the generator so family members know what to do to restore power.
NOW GET TO WORK AND FIGURE OUT WHAT YOU NEED FOR YOUR HOME OR BUSINESS STANDBY GENERATOR!
HOME STANDBY GENERATORS
If you want the convenience, security, and comfort of a generator but don't want to venture out in inclement weather to get it started, you might want to consider getting an emergency standby generator.
These personal power plants supply electricity to the majority of your house, not just to a few selected circuits. The all-weather generators are installed outside like a central air conditioner and are wired through an automatic transfer switch to the main electrical panel.
The units run on natural gas, propane, or diesel fuel. Some systems can even be connected to a home's natural gas line, eliminating the need to fill fuel tanks.
When the power goes out, there's a slight delay of 15 to 20 seconds, then the generator automatically kicks on - whether you're home or not - and continues running until power is restored, when it will automatically shut off. If you have critical applications such as life support equipment, computers or similar systems, you can install a UPS (uninterruptible power supply, a battery in a special box), and there will be no interruption of power to these devices while the generator starts up.
These systems are becoming increasingly popular in newer homes with sophisticated computers and electronics, and in rural areas where prolonged power outages are common. To see our extensive line of home standby generators, Just Click > Residential & Commercial Packaged Systems.
For large generators fro 14 kW to 2000 kW, Just Click > Industrial GenSets - Single Phase or Industrial GenSets - Three Phase
PORTABLE GENERATORS
A growing number of Americans are converting their portable gasoline generators into emergency backup power systems.
The minimum size recommended for home-emergency use is a 5,000-watt generator (starting around $600), which can power multiple appliances for 8 hours.
Portable generators are available on our site and can be shipped anywhere around the country. Retail stores carry them also but they become scarce during a blackout and often it is difficult to find the cords, plugs, transfer switches and other parts needed. Most generators sold in hardware stores are low quality, price cutting types of units. We sell contractor quality, built to last.
We carry several brands of portable generators including: VoltMaster Honda, Yamaha, Baldor, Winco, Onan, Robin and others. For more information on portable generators, Just Click > Portable Generators.
Extension Cords
The most common way to use a portable generator is to place it outdoors, then run an extension cord(s) through an open window or door to the chosen appliance. This approach works well for smaller generators because you can only plug in one or two items. You must connect the item directly unless you use a transfer switch. NOTE: You cannot run a generator indoors, not even in the garage, because a generator makes carbon-monoxide which is odorless an color-less and it can kill you and your family.
Be sure to use appropriately sized power cords to carry the electric load. If you use an undersized cord, you can potentially damage the generator and appliances.
Extension cords are rated by "gauges." For example, the most common size for generator use is 14, 12 and 10 gauge. The smaller the gauge number, the thicker the cord and the more electricity it can carry.
Extension cords have several other drawbacks. First, most extension cords can't be plugged into a furnace, well pump, or ceiling-light fixture. And, if they are placed under rugs or carpets, heat can build up and spark a fire.
For more information on cords, plugs and inlets boxes to use with your transfer switch, Just Click > Cords, Plugs and Outlet Boxes.
To see a summary of issues involving portable generator see Portable vs Stationary generators.
GENERATOR SIZES AND TYPES FOR HOME OR BUSINESS
Home and business owners often ask us two questions:
1. What size generator do I need? and
2. Should use a portable or stationary generator for my home or business? This great article by Coleman, a leading manufacturer of home generators was adapted to answer this question for you. Read each section carefully and you will see how each type of generator fits into you power backup planning.
Power Generation, What Size Do I Need?
In the past, enduring a power outage was as simple as lighting a candle and the fireplace. Not anymore. Without electricity, basements can flood. Security systems can falter. Home businesses can fail. Many homeowners are unable or unwilling to wait out the next power outage, so they are installing backup power systems in their homes. The first step in purchasing a backup power source is figuring out how much power you need. Power generation systems are rated according to the number of kilowatts (kW) of electricity they produce. The following chart quickly summarizes how much electricity various power generators can produce.
1. What size generator do I need? and
2. Should use a portable or stationary generator for my home or business? This great article by Coleman, a leading manufacturer of home generators was adapted to answer this question for you. Read each section carefully and you will see how each type of generator fits into you power backup planning.
Power Generation, What Size Do I Need?
In the past, enduring a power outage was as simple as lighting a candle and the fireplace. Not anymore. Without electricity, basements can flood. Security systems can falter. Home businesses can fail. Many homeowners are unable or unwilling to wait out the next power outage, so they are installing backup power systems in their homes. The first step in purchasing a backup power source is figuring out how much power you need. Power generation systems are rated according to the number of kilowatts (kW) of electricity they produce. The following chart quickly summarizes how much electricity various power generators can produce.
Rated Watts
Description
Degrees of Power
5 kW
A basic system that can restore power to multiple "survival appliances".
Four lights, furnace fan, sump pump and refrigerator/freezer
6.5 kW
A small system to keep all the survival appliances operating and a few extras.
Survival appliances plus family room.
8 kW
A mid-Sized system to help you weather powerless days and nights.
Survival appliances plus family room and home office.
10 kW
An emergency backup power system providing comfort and security.
Survival appliances plus family room, home office and kitchen.
15 kW
A powerful system with enough energy to run a small home.
Survival appliances plus family room, home office kitchen and laundry room.
25 kW
A mini-power plant that can run a small to mid-sized home or business.
All of the above plus an air conditioning system.
30 kW and up
A mini-power plant that can run a mid-sized to large home or business.
All of the above and more. Live in total comfort.
Thursday, August 27, 2009
GENERATOR AMP RATINGS - THREE PHASE EXTENDED
3 PHASE AMPERES - 80% POWER FACTOR* (Extended Table)
kW Times 1000 divided by (Volts*1.73) *.80
This chart approximates the amperage of a generator based on the size of the generator and the load on the generator at 100 percent of capacity. Please note that this table is intended to be used as an estimator is not an exact representation due to various factors that can increase or decrease amperage. Elevation, temperature, fuel quality, age, wire size and length and other factors can decrease the amount of power a specific installation can generate.
click here for detail
kW Times 1000 divided by (Volts*1.73) *.80
This chart approximates the amperage of a generator based on the size of the generator and the load on the generator at 100 percent of capacity. Please note that this table is intended to be used as an estimator is not an exact representation due to various factors that can increase or decrease amperage. Elevation, temperature, fuel quality, age, wire size and length and other factors can decrease the amount of power a specific installation can generate.
click here for detail
GENERATOR SIZING PROCEDURE - WHAT SIZE DO I NEED?
Generator Sizing Guide
Power requirements must be determined to properly size your generator. We are providing some steps to assist you in approximating the size generator for your power needs. Please keep in mind that unless you are qualified, you should use a certified electrician to determine your power needs. At Americas Generators it is our goal to assist our customers in any way possible. If you have any questions, please do not hesitate to contact us.
STEPS TO DETERMINE GENERATOR REQUIREMENTS
Answer these questions, write down your answers.
Determine your need, What do you want to run in an emergency and why?
Do you want the generator to operate part or all of your home or office?
Identify the appliances and/or tools the generator will need to power.
Make a list and fill in the blanks. Click here for a printable form Use the form to make a list.
Determine the wattage for each appliance and tool you plan to use frequently.
Click here to get a list of common appliance's motors and other power uses.
Identify motor and pump requirements.
Use the motor and pump table by clicking Motor Table
Calculate and total the wattage for the motors and pumps frequently used.
Always use starting watts, not running watts, when determining the correct electrical load requirements. Calculations - Doing It Exactly
Total the wattage of the appliances & tools and the motors & pumps..
Keep in mind that you will not operate everything all at once. Therefore, for emergency use you don’t need to size the generator to operate everything just what you need to survive and be comfortable.Wattage Guide
Convert watts into kilowatts by dividing the total watts to determine the generator size required. Conversions
Please note that it is suggested, although not absolutely necessary, to size the generator 20-25% over the size you determine your needs to be. This will allow room for future growth. For example, if you determine that you will need a 15 kW generator then it is advisable to purchase an 18 kW generator to accommodate future expansion.
Power requirements must be determined to properly size your generator. We are providing some steps to assist you in approximating the size generator for your power needs. Please keep in mind that unless you are qualified, you should use a certified electrician to determine your power needs. At Americas Generators it is our goal to assist our customers in any way possible. If you have any questions, please do not hesitate to contact us.
STEPS TO DETERMINE GENERATOR REQUIREMENTS
Answer these questions, write down your answers.
Determine your need, What do you want to run in an emergency and why?
Do you want the generator to operate part or all of your home or office?
Identify the appliances and/or tools the generator will need to power.
Make a list and fill in the blanks. Click here for a printable form Use the form to make a list.
Determine the wattage for each appliance and tool you plan to use frequently.
Click here to get a list of common appliance's motors and other power uses.
Identify motor and pump requirements.
Use the motor and pump table by clicking Motor Table
Calculate and total the wattage for the motors and pumps frequently used.
Always use starting watts, not running watts, when determining the correct electrical load requirements. Calculations - Doing It Exactly
Total the wattage of the appliances & tools and the motors & pumps..
Keep in mind that you will not operate everything all at once. Therefore, for emergency use you don’t need to size the generator to operate everything just what you need to survive and be comfortable.Wattage Guide
Convert watts into kilowatts by dividing the total watts to determine the generator size required. Conversions
Please note that it is suggested, although not absolutely necessary, to size the generator 20-25% over the size you determine your needs to be. This will allow room for future growth. For example, if you determine that you will need a 15 kW generator then it is advisable to purchase an 18 kW generator to accommodate future expansion.
Tuesday, August 25, 2009
Frequently Asked Generator Questions
Q1. How large a generator do I need for my home or small business?
A. Every home or small business is different. The size of the generator is based on the type of appliances, equipment, pumps, air-conditioners and other electrical devices requiring power.
Your service panel is normally rated at 200 amps @ 240 volts and the average home uses approximately 140 to 160 amps of 240 volts power to operate everything at the same time. Your larger appliances (well pump, kitchen stove, water heater, electric dryer, electric heater and heat pump system) will typically use 240 volts power and the lights and other smaller appliances will use 120 volt power. It is important to consider this difference in doing the load calculations because the important calculation is to determine just how many amps and watts you will need. For example, if you want to operate your refrigerator (20 amps x 120 volts = 2400 watts), freezer (20 amps x 120 volts = 2400 watts), electric hot water heater (20 amps x 240 volts = 4800 watts), washer (20 amps x 120 volts = 2,400 watts) and electric dryer (30 amps x 240 volts = 7200 watts) all at the same time you will need approximately 19,200 watts to meet the breaker requirements for these appliances. In reality the breakers are typically oversized for safety by 10 to 15% and the above appliances will not all operate at peak at the same time and the above load can be handled with a 15,000 watt (15 kW) generator set (GenSet).
The major appliances, pumps, or other motor driven devices that you plan to operate with your generator system need to be considered when calculating the minimum size of a generator. Sizing a generator system requires you to honestly assess your needs and wants.
Generally you can cut through all this stuff with these simple rules. If you have 100 Amp service panel, use a 8-12 kW GenSet (use larger if you have air conditioning). If you have a 200 Amp service panel, use a 15-20 kW GenSet (again use the larger size if you have air conditioning or large well pump). If you have a 400 amp service panel, use a 30-50 kW GenSet (if you have lots of air conditioning or other larger loads use the large size in the range).
There are some other power requirements that will help you establish a minimum size generator system: 1) Well pumps usually require 2-3 times the run watts to start the pump.2) Combination heat pump/air-conditioner systems are normally on 60 amp (14400 watts) breakers and use 30 amps (7200 watts) for the heat cycle and the same for the air-conditioning function.3) Electric furnaces are typically on 50 amp breaker. (6,000 watts at 120 volts) 4) Hot water heaters normally use between 20 amps (4,500 watts) and 25 amps (6,000 watts) depending on the size and efficiency design5) Electric kitchen stoves are usually on 50 amp (6,000 watts) breakers.6) Air-conditioners come in a variety of sizes and ratings which need to be calculated based on the BTU output. A 2-ton unit is rated at 24,000 BTU's 20 amps (5000 watts) to start the unit and 15 amps (3,600 watts) to operate it.
Q2. What is the advantage of buying a generator direct over the internet through GeneratorJoe as opposed to buying from a local dealer?
A. GeneratorJoe supplies many of the best generator products available in the world today at the most competitive prices available. Our factory direct program removes the middle man and generally saves the customer 10-30% off the normal dealer price. Retail stores are usually restricted to one brand. We have a wide selection of products so you get the best model for your application at the best possible price. GeneratorJoe gives you the selection and services needed to make it easier to own a generator system.
GeneratorJoe provides: Sales: Competent and knowledgeable salespeople to discuss all your requirements and application and to properly size and calculate all motor starting requirements.Customer Service: parts and warranty assistance on all products purchased from GeneratorJoe.Technical Support: trouble-shooting service via phone, fax, or e-mail. Shipping to your door or export freight forwarder Products: We have the best products on the market at the best Prices. We don't sell junk equipment, cheap imports, cheap hardware store brands or low price volume products that most generator companies wont sell. If we sell it, its quality.
Q3. Single or Three Phase? Is a 3-phase generator suitable for the average homeowner or small business?
A. Yes and No. Some manufacturers use an over-sized 12-wire 3-phase generator end for single-phase applications. This allows the generator system to be used for both single-phase and 3-phase applications. The advantage of using an over-sized generator in a 3-phase or single-phase application is to meet motor starting requirements without having to use an overly large diesel engine. For most residential applications are 1 phase (single phase) and using a 3 phase generator is a waste of money and fuel. If you have a 3 phase service you will need a 3 phase generator otherwise use a unit built as single phase. Be cautious, some dealers will try to sell you a 3 phase generator "strapped" for single phase. You will lose 30% of the generators output and use 30% more fuel to make single phase power.
If your generator system will power air-conditioning units, pumps, heat pumps, well pumps, welders, or irrigation pumps you need assistance calculating your service size let us know. We will make sure you get the right size. GeneratorJoe provides this service free. We will insure that the when your generator is built that the voltage is set and the GenSet is tested at the factory before shipment
Q4. What is the function of the electronic controller on a GenSet?
A. Most of the engine/generator controllers used today are digital and are designed to provide control of the generator set. (GenSet). The controller system monitors the operation of the engine and generator functions. Typical safety items include low oil pressure, high temperature, engine start over-crank, over/under frequency (speed), low coolant level etc. Modern digital controllers for residential or small business applications are typically a simplified LED indicators a start-stop button with or without auto-start. If the generator has auto-start, the controller can be used to interface with an automatic transfer switch or inverter/battery system to start and stop automatically. Usually manual controls are provided on al generators including those with auto-start. Advanced controllers provides real time monitoring of volts, hertz and amperage in addition to the basic engine/generator safeties and auto-start functions. Complex controllers typically installed on larger generator systems provide engine safeties and shutdowns for low oil pressure, high temperature, engine start over-crank, over/under-speed, low coolant level and also have indicators for low fuel level, KVA output, KW output, power factor (PF), engine & generator gauges in real time. Larger generators often have a communication capability for remote monitoring and starting.
Q5. Can I use a portable generator for an automatic starting system?
A. Generally No. Most portable generators do NOT have the capability to auto-start. The generator must have an electric starter, electric choke (for gasoline units) and the start and stop controls and safety sensors to be able to start and stop automatically. The cost of auto-start and safety equipment generally increases the price of portable equipment so much that no one would buy them, so they are not manufactured.
Q6. What kind of generator should I purchase - gaseous or diesel?
A. There are a number of factors to consider in evaluating the differences between a gaseous (natural gas or propane) powered engine.
See our Generator Fuel chart for a list of positive and negative factors of fuel and generator types. GeneratorJoe recommends the use of liquid-cooled diesel engine GenSets in hurricane environments where the potential for long run times is high or for prime duty applications where the generator is the prime source of power. GeneratorJoe carries a number of high quality diesel powered generator products designed to provide years of trouble-free operation.
Q7. Do 3600 RPM diesel generators last as long as 1800 RPM GenSets?
A. Generally the 1800 RPM engine speed will out last the 3600 RPM units. Most small diesel portable generators in the 3 kW to 6 kW class are air-cooled 3600 RPM engines are designed to keep the weight and cost down. Generally air cooled GenSets are for temporary use and have short lives. If you need a long term solution or have several outages a year or long outage times use a liquid cooled 1800 RPM GenSet.
Q8. We want the power generator to supply power to a computer system in our home or business; what are the issues involved?
A. Most generators sold by GeneratorJoe are designed to power computers. The majority of 1800 RPM and 3600 RPM liquid-cooled generators use automatic voltage regulated (AVR-Electronic module) generator systems that provide from 1% to 2% voltage regulation, which meets or exceeds the local utility power specifications. Some portable generators with capacitor regulation (voltage control from 5% to 10% or without AVR) can present a problem for some computer systems if the computer is plugged directly into the electrical circuit and does not use a battery regulated power supply or UPS. Another factor that impacts computers is the speed control, (which effects frequency in hertz) which is normally 3-5% with an engine mechanical governor regulation and .25% to .5% regulation with an electronic engine governor system. Mechanically governed systems are normally sufficient to provide clean power for sensitive electronics like computers. For computer service centers and other communication applications like radio and TV stations that use a UPS system, they usually use of an electronic governor. Electronic governors not only maintain engine speed more accurately but with a much quicker response time to no-load to load conditions which helps prevent voltage drop. Most industrial diesel engines equipped with auto-start can be equipped from the factory with an electronic governor depending on the manufacture and engine design, however the costs will be much higher than a mechanical governor and may not be necessary for most uses. GeneratorJoe has developed a series of Cummins diesel powered open and sound enclosed GenSets rated for both standby (emergency service less than 500 hours per year) or prime (main power source over 500 hours per year). The new GeneratorJoe Cummins powered Warrior and Gladiator Series represents one of the most competitively priced full featured quality diesel generators on the market today.
Q9. What does the term "Wet Stacking" mean in a diesel engine?
A. Diesel engines are designed to operate with a load. When a diesel engine operates considerably below the rated output level the engine can start to over-fuel or "Wet Stack". Diesel engines perform most efficiently in the 70-80% range of rated output. When an engine operates for a prolonged period of time below 40% of the rated output it begins to over-fuel. This is similar to driving a car in the City at slow speeds for long periods. Wet Stacking occurs because the injection tips began to carbonize and disrupt the fuel spray pattern. Commercial generator systems often have widely varying loads with some low output conditions often have wet stacking problems because of the diverse load applications and owners artificially load the generator with an automatic load bank. A load bank will place a "false" load on the generator system to keep the diesel engine properly loaded. Once a diesel engine begins to "wet stack" the only way to correct the problem is to load the engine for a couple of hours to burn off the excess fuel and clean up the engine. This is seldom necessary in a residential or commercial application. Generally, electronically controlled engines and engines with advanced emission systems are less likely to "wet stack". It is for this reason that proper sizing and design is important. GeneratorJoe can help you with all your sizing and design considerations.
Q10. What kind of maintenance will my diesel generator need and how complicated is it for the average homeowner or small business?
A. Diesel engines require routine maintenance for long-life service. The normal maintenance requirements are about the same as owning a diesel powered vehicle - oil, oil filter, air filter and fuel filter. In tropical and cold climates it is advisable to have a water-fuel separation filter system installed. Water or moisture in diesel fuel can be damaging to a diesel engine because the water properties create advanced ignition and accelerated detonation. The engine will need an oil change every 250 to 500 hours depending on the dust conditions or annually in the case of standby generators. Change the oil filter when you change the oil. Air filters need to be changed when they appear dirty. Check air filters whenever you inspect the generator or change the oil. Fuel filters are normally changed every 250 to 300 hours depending on how clean the fuel is. Inspect fuel filters when you fill the tanks, during oil changes and any time you inspect the generator. If the generator has a service schedule, follow it.The generator end (AC alternator) will not require any service unless you live in a dusty environment. In dusty environments we recommend you use a high pressure (50 PSI) air hose and occasionally blow out the dust from the generator system. Dirt and heavy dust particles can cause shorts in the internal wiring coatings under the right conditions.
A. Every home or small business is different. The size of the generator is based on the type of appliances, equipment, pumps, air-conditioners and other electrical devices requiring power.
Your service panel is normally rated at 200 amps @ 240 volts and the average home uses approximately 140 to 160 amps of 240 volts power to operate everything at the same time. Your larger appliances (well pump, kitchen stove, water heater, electric dryer, electric heater and heat pump system) will typically use 240 volts power and the lights and other smaller appliances will use 120 volt power. It is important to consider this difference in doing the load calculations because the important calculation is to determine just how many amps and watts you will need. For example, if you want to operate your refrigerator (20 amps x 120 volts = 2400 watts), freezer (20 amps x 120 volts = 2400 watts), electric hot water heater (20 amps x 240 volts = 4800 watts), washer (20 amps x 120 volts = 2,400 watts) and electric dryer (30 amps x 240 volts = 7200 watts) all at the same time you will need approximately 19,200 watts to meet the breaker requirements for these appliances. In reality the breakers are typically oversized for safety by 10 to 15% and the above appliances will not all operate at peak at the same time and the above load can be handled with a 15,000 watt (15 kW) generator set (GenSet).
The major appliances, pumps, or other motor driven devices that you plan to operate with your generator system need to be considered when calculating the minimum size of a generator. Sizing a generator system requires you to honestly assess your needs and wants.
Generally you can cut through all this stuff with these simple rules. If you have 100 Amp service panel, use a 8-12 kW GenSet (use larger if you have air conditioning). If you have a 200 Amp service panel, use a 15-20 kW GenSet (again use the larger size if you have air conditioning or large well pump). If you have a 400 amp service panel, use a 30-50 kW GenSet (if you have lots of air conditioning or other larger loads use the large size in the range).
There are some other power requirements that will help you establish a minimum size generator system: 1) Well pumps usually require 2-3 times the run watts to start the pump.2) Combination heat pump/air-conditioner systems are normally on 60 amp (14400 watts) breakers and use 30 amps (7200 watts) for the heat cycle and the same for the air-conditioning function.3) Electric furnaces are typically on 50 amp breaker. (6,000 watts at 120 volts) 4) Hot water heaters normally use between 20 amps (4,500 watts) and 25 amps (6,000 watts) depending on the size and efficiency design5) Electric kitchen stoves are usually on 50 amp (6,000 watts) breakers.6) Air-conditioners come in a variety of sizes and ratings which need to be calculated based on the BTU output. A 2-ton unit is rated at 24,000 BTU's 20 amps (5000 watts) to start the unit and 15 amps (3,600 watts) to operate it.
Q2. What is the advantage of buying a generator direct over the internet through GeneratorJoe as opposed to buying from a local dealer?
A. GeneratorJoe supplies many of the best generator products available in the world today at the most competitive prices available. Our factory direct program removes the middle man and generally saves the customer 10-30% off the normal dealer price. Retail stores are usually restricted to one brand. We have a wide selection of products so you get the best model for your application at the best possible price. GeneratorJoe gives you the selection and services needed to make it easier to own a generator system.
GeneratorJoe provides: Sales: Competent and knowledgeable salespeople to discuss all your requirements and application and to properly size and calculate all motor starting requirements.Customer Service: parts and warranty assistance on all products purchased from GeneratorJoe.Technical Support: trouble-shooting service via phone, fax, or e-mail. Shipping to your door or export freight forwarder Products: We have the best products on the market at the best Prices. We don't sell junk equipment, cheap imports, cheap hardware store brands or low price volume products that most generator companies wont sell. If we sell it, its quality.
Q3. Single or Three Phase? Is a 3-phase generator suitable for the average homeowner or small business?
A. Yes and No. Some manufacturers use an over-sized 12-wire 3-phase generator end for single-phase applications. This allows the generator system to be used for both single-phase and 3-phase applications. The advantage of using an over-sized generator in a 3-phase or single-phase application is to meet motor starting requirements without having to use an overly large diesel engine. For most residential applications are 1 phase (single phase) and using a 3 phase generator is a waste of money and fuel. If you have a 3 phase service you will need a 3 phase generator otherwise use a unit built as single phase. Be cautious, some dealers will try to sell you a 3 phase generator "strapped" for single phase. You will lose 30% of the generators output and use 30% more fuel to make single phase power.
If your generator system will power air-conditioning units, pumps, heat pumps, well pumps, welders, or irrigation pumps you need assistance calculating your service size let us know. We will make sure you get the right size. GeneratorJoe provides this service free. We will insure that the when your generator is built that the voltage is set and the GenSet is tested at the factory before shipment
Q4. What is the function of the electronic controller on a GenSet?
A. Most of the engine/generator controllers used today are digital and are designed to provide control of the generator set. (GenSet). The controller system monitors the operation of the engine and generator functions. Typical safety items include low oil pressure, high temperature, engine start over-crank, over/under frequency (speed), low coolant level etc. Modern digital controllers for residential or small business applications are typically a simplified LED indicators a start-stop button with or without auto-start. If the generator has auto-start, the controller can be used to interface with an automatic transfer switch or inverter/battery system to start and stop automatically. Usually manual controls are provided on al generators including those with auto-start. Advanced controllers provides real time monitoring of volts, hertz and amperage in addition to the basic engine/generator safeties and auto-start functions. Complex controllers typically installed on larger generator systems provide engine safeties and shutdowns for low oil pressure, high temperature, engine start over-crank, over/under-speed, low coolant level and also have indicators for low fuel level, KVA output, KW output, power factor (PF), engine & generator gauges in real time. Larger generators often have a communication capability for remote monitoring and starting.
Q5. Can I use a portable generator for an automatic starting system?
A. Generally No. Most portable generators do NOT have the capability to auto-start. The generator must have an electric starter, electric choke (for gasoline units) and the start and stop controls and safety sensors to be able to start and stop automatically. The cost of auto-start and safety equipment generally increases the price of portable equipment so much that no one would buy them, so they are not manufactured.
Q6. What kind of generator should I purchase - gaseous or diesel?
A. There are a number of factors to consider in evaluating the differences between a gaseous (natural gas or propane) powered engine.
See our Generator Fuel chart for a list of positive and negative factors of fuel and generator types. GeneratorJoe recommends the use of liquid-cooled diesel engine GenSets in hurricane environments where the potential for long run times is high or for prime duty applications where the generator is the prime source of power. GeneratorJoe carries a number of high quality diesel powered generator products designed to provide years of trouble-free operation.
Q7. Do 3600 RPM diesel generators last as long as 1800 RPM GenSets?
A. Generally the 1800 RPM engine speed will out last the 3600 RPM units. Most small diesel portable generators in the 3 kW to 6 kW class are air-cooled 3600 RPM engines are designed to keep the weight and cost down. Generally air cooled GenSets are for temporary use and have short lives. If you need a long term solution or have several outages a year or long outage times use a liquid cooled 1800 RPM GenSet.
Q8. We want the power generator to supply power to a computer system in our home or business; what are the issues involved?
A. Most generators sold by GeneratorJoe are designed to power computers. The majority of 1800 RPM and 3600 RPM liquid-cooled generators use automatic voltage regulated (AVR-Electronic module) generator systems that provide from 1% to 2% voltage regulation, which meets or exceeds the local utility power specifications. Some portable generators with capacitor regulation (voltage control from 5% to 10% or without AVR) can present a problem for some computer systems if the computer is plugged directly into the electrical circuit and does not use a battery regulated power supply or UPS. Another factor that impacts computers is the speed control, (which effects frequency in hertz) which is normally 3-5% with an engine mechanical governor regulation and .25% to .5% regulation with an electronic engine governor system. Mechanically governed systems are normally sufficient to provide clean power for sensitive electronics like computers. For computer service centers and other communication applications like radio and TV stations that use a UPS system, they usually use of an electronic governor. Electronic governors not only maintain engine speed more accurately but with a much quicker response time to no-load to load conditions which helps prevent voltage drop. Most industrial diesel engines equipped with auto-start can be equipped from the factory with an electronic governor depending on the manufacture and engine design, however the costs will be much higher than a mechanical governor and may not be necessary for most uses. GeneratorJoe has developed a series of Cummins diesel powered open and sound enclosed GenSets rated for both standby (emergency service less than 500 hours per year) or prime (main power source over 500 hours per year). The new GeneratorJoe Cummins powered Warrior and Gladiator Series represents one of the most competitively priced full featured quality diesel generators on the market today.
Q9. What does the term "Wet Stacking" mean in a diesel engine?
A. Diesel engines are designed to operate with a load. When a diesel engine operates considerably below the rated output level the engine can start to over-fuel or "Wet Stack". Diesel engines perform most efficiently in the 70-80% range of rated output. When an engine operates for a prolonged period of time below 40% of the rated output it begins to over-fuel. This is similar to driving a car in the City at slow speeds for long periods. Wet Stacking occurs because the injection tips began to carbonize and disrupt the fuel spray pattern. Commercial generator systems often have widely varying loads with some low output conditions often have wet stacking problems because of the diverse load applications and owners artificially load the generator with an automatic load bank. A load bank will place a "false" load on the generator system to keep the diesel engine properly loaded. Once a diesel engine begins to "wet stack" the only way to correct the problem is to load the engine for a couple of hours to burn off the excess fuel and clean up the engine. This is seldom necessary in a residential or commercial application. Generally, electronically controlled engines and engines with advanced emission systems are less likely to "wet stack". It is for this reason that proper sizing and design is important. GeneratorJoe can help you with all your sizing and design considerations.
Q10. What kind of maintenance will my diesel generator need and how complicated is it for the average homeowner or small business?
A. Diesel engines require routine maintenance for long-life service. The normal maintenance requirements are about the same as owning a diesel powered vehicle - oil, oil filter, air filter and fuel filter. In tropical and cold climates it is advisable to have a water-fuel separation filter system installed. Water or moisture in diesel fuel can be damaging to a diesel engine because the water properties create advanced ignition and accelerated detonation. The engine will need an oil change every 250 to 500 hours depending on the dust conditions or annually in the case of standby generators. Change the oil filter when you change the oil. Air filters need to be changed when they appear dirty. Check air filters whenever you inspect the generator or change the oil. Fuel filters are normally changed every 250 to 300 hours depending on how clean the fuel is. Inspect fuel filters when you fill the tanks, during oil changes and any time you inspect the generator. If the generator has a service schedule, follow it.The generator end (AC alternator) will not require any service unless you live in a dusty environment. In dusty environments we recommend you use a high pressure (50 PSI) air hose and occasionally blow out the dust from the generator system. Dirt and heavy dust particles can cause shorts in the internal wiring coatings under the right conditions.
Step by Step Basic Generator Information
Buying a Generator - Considerations
Engine block. For long life and quiet operation we recommend four cycle, liquid cooled, industrial duty diesel engines.
Air or liquid cooling. Air-cooled engines require a tremendous amount of air and may require ducting and they are somewhat noisier. Liquid cooling offers quieter operation, more even temperature control and therefore longer engine life. Modern air cooled engines are suitable for many applications, especially short run, portable or standby uses.
Intake Air. All quality generators have intake air filters with replaceable filter elements. Today even small portables have replaceable air cleaners.
Mufflers. Most generator come equipped with an industrial grade muffler. One good investment is a residential or critical muffler that is much quieter and lasts longer. All enclosed generators should be equipped with at least a residential and preferably a critical muffler.
Lubrication. The lubrication system should have a full flow, spin-on oil filter. Larger generators should have a filter bypass. Most generators today have low oil alarms and shutdowns, make sure the generator you select has this valuable feature, its simply a must have protection.
Major brand of engine. We do not know why people would even consider an inferior "scrap metal" unit or "off brand" engine, you will not be able to obtain the necessary parts, service and support. Many engines come with a box of spare parts including pistons, rings and bearings because your going to need them all. Save yourself some grief and buy a major brand of engine. If you buy a junk engine, we wont service it and most other reputable dealers won't either.
Electrical system and circuit breakers. Standard 12 volt system should include at least the following: 1) Quality starter motor and battery. Larger generators should include a charging alternator with a solid state voltage regulator. 2) Larger diesel units should come with a pre-heat switch and all generators should have a start/stop switch. 3) Al generators should have a safety shutdown system to protect the engine in case of oil pressure loss, generator over-speed or over-crank and high water (or operating) temperature. 4) System circuit breaker to protect the generator. On small systems and portables there should be a circuit breaker on each circuit.
INDOOR MOUNTING
We do not recommend locating generator sets indoors in residential applications and small commercial and industrial applications. The primary reason to avoid indoor installation is safety. Carbon monoxide gas is odorless, colorless and can accumulate in closed spaces. You can walk into a room full of carbon monoxide and be overcome. A gas leak in space attached to your home can kill you and your family.
In addition to safety, it costs more to install a GenSet indoors than for the same GenSet provided with the factory weatherproof housing. When a GenSet is installed indoors, the building must be designed carefully to handle ventilation to remove heat and any fumes due to fuel, exhaust, lubrication and starting batteries. The radiator must be provided with a duct adapter that interfaces properly with louvers on an outside wall of the building. Adequate air intake flow must be available not only for the radiator fan but also for cooling the alternator. The engine exhaust piping and muffler must be tight to prevent any leaks that would allow dangerous carbon monoxide to accumulate inside the building.
Generally, the room or space in which the generator operates, should not exceed 100 F. We recommend keeping it under 85 F if possible. Generator installations require an intake of cool, clean air and an outlet vent for hot air. Whenever possible the cool air should be drawn over the alternator (or generator end) to help keep the alternator cool. The size of the space affects the room temperature (the smaller the space the generator runs in, the higher the room temperature is likely to be), smaller spaces may require ducting. The size of the generator and the outside air temperature or climate must be considered. In an indoor installation, increasing these vent sizes may cool the room down to acceptable levels and ensure “positive” airflow. Positive airflow is cool, clean air in and hot air out, as opposed to circulating hot air inside the room. Generator cooling fans move moisture as well as air. Moist air is corrosive to a GenSets copper windings, so make sure air inlets are positioned to minimize moisture intake.
Automatic fire suppression systems may also be required. Check with your local fire codes. You should also contact your fire insurance provider to determine if an indoor GenSet is even permitted.
Installation engineered to meet all the above requirements and all safety codes can still become a hazard later. For an installation to remain safe, it has to be regularly inspected and maintained to ensure that leaks or other dangerous conditions do not develop with age or use. Sites that do not have a knowledgeable maintenance staff trained to support an indoor generator set should not install a unit inside a building.
Another factor is the initial cost. It is impossible to construct a building to house a GenSet at a cost as low as the factory housing that can be ordered with the GenSet. And even if the building already exists, the design expense and costs to adapt it for a generator set installation usually will exceed the enclosure cost available from the GenSet manufacturer. For a small GenSet the cost of an open unit with duct adaptor and exhaust pipe kit is as little as $600 less than the same GenSet with the factory weather housing. The additional costs for just the exhaust thimble and louvers exceed that savings.
Please read Policy, Warranties and Disclaimers. You as the buyer and user of generators sold by GeneratorJoe assume all risk and liability in connection with all equipment purchased
AC CONNECTIONS
Now that you have decided to purchase a generator, there are several considerations you must keep in mind when choosing which unit to buy, where to install it and how to install it. This guide will help you select a generator using a step by step method. Choosing the right machine is not difficult if you take the time to analyze your requirements carefully. GeneratorJoe is here to help, if you get confused or have a question, ask us.
You need to know a few terms and have a basic understanding of the different types of generator sets and their operating principles. We will explain in simple terms.
You should have your equipment installed by an expert. A knowledgeable person, who knows the electric code, can do wiring and simple plumbing can do the installation, but you will have to know what your doing. Installation may require expert assistance and must adhere to local codes and regulations, not only to obey the law but to make sure you don't void your insurance by installing equipment illegally or without permits. We recommend that you have a contractor do your installation or, at the very least, have him provide professional advice. It is up to you to make sure the installation is done correctly.
You should have your equipment installed by an expert. A knowledgeable person, who knows the electric code, can do wiring and simple plumbing can do the installation, but you will have to know what your doing. Installation may require expert assistance and must adhere to local codes and regulations, not only to obey the law but to make sure you don't void your insurance by installing equipment illegally or without permits. We recommend that you have a contractor do your installation or, at the very least, have him provide professional advice. It is up to you to make sure the installation is done correctly.
PORTABLE OR STATIONARY?
st homeowners first think of portable generators rather then stationary generators. If you want to haul a generator outside or put one outside in a shed and plug in cords when there is a power outage, it can be done. You will not necessarily save any money doing it but if you have a use for the portable generator for non-emergency times then it might be an alternative. It has been our experience that it is more economical and less hassle to purchase a stationary system and power the whole house or business. Not only do you get more power for the dollar but your family and/or employees don't have to do anything to have emergency power. Do you want your wife, children or employees hauling out equipment and plugging things in and starting up the system, switching the transfer switch and having to refuel? At some point all of this becomes ridiculous and costs you more in staff time and potential liability then its worth.
STAND-BY OR PRIME?
The first determination you will need to make is whether you will require stand-by or prime power. Simply stated, prime power is required when you have no other source of power or you are using the system as you prime means of power. Any generator that is used everyday or on a fixed schedule to provide power is considered a prime power generator. Another word for prime is "continuous". If you need a prime power generator, use the generators prime or continuous rating as a guide.
A standby set is a backup to normal utility power. Standby units are used only when your utility power is not available and will not be used frequently. Many stand by generators run at 3600 RPM and are not designed for constant daily use. Another word for standby is "emergency". If you need a standby power generator, use the generators standby or emergency rating as a guide.
A standby set is a backup to normal utility power. Standby units are used only when your utility power is not available and will not be used frequently. Many stand by generators run at 3600 RPM and are not designed for constant daily use. Another word for standby is "emergency". If you need a standby power generator, use the generators standby or emergency rating as a guide.
GENERATOR PHASES
Generator sets produce either single or three phase power. You should use the type of power your panel provides. Residences and small business generally use single phase. Three-phase power is used for medium to large businesses especially where power is used for motor starting and running. Three phase generators are set up to produce 120/208 or 277/480 volts. Single-phase sets are 120 or 120/240. Use the low voltage to run domestic appliances and the high voltage for your motors, heaters, stoves and dryers. Your service panel is either single phase or three phase, you don't need a three phase generator if your panel is only single phase. Check with your electrician before you begin your search.
ENERATOR AMPERAGE
Your service panel is a good place to start. Go and look at your service panel and see what the amperage is. If the panel is 100 Amps that tells you that your won't need more then 100 amps of power. As the panel gets bigger so will your generator needs. It is possible to install a generator to power only a small portion of your service panel, if you install appropriate sub-panels to sort out what will and will not be powered.
FUEL: GAS OR DIESEL?
We recommend diesels due to their longevity and lower operating costs. Today’s modern diesels are quiet and normally require much less maintenance than comparably sized gas (natural gas or propane) units. Fuel costs per kW produced with diesels is normally thirty to fifty percent less than gas units.
1800 rpm water cooled diesel units operate on average 12,000 to 30,000 hours before major maintenance is required.
1800 rpm water cooled gas units normally operate 6,000 to 10,000 hours because they are built on a lighter duty gasoline engine block. Gas units burn hotter (higher BTU of the fuel) so you will see generally see somewhat shorter lives than the diesel units
3600 rpm air-cooled gas units are normally replaced – not overhauled at 500 to 1500 hours. These are "stand-by" generators, not intended to be run long hours or very often.
1800 rpm water cooled diesel units operate on average 12,000 to 30,000 hours before major maintenance is required.
1800 rpm water cooled gas units normally operate 6,000 to 10,000 hours because they are built on a lighter duty gasoline engine block. Gas units burn hotter (higher BTU of the fuel) so you will see generally see somewhat shorter lives than the diesel units
3600 rpm air-cooled gas units are normally replaced – not overhauled at 500 to 1500 hours. These are "stand-by" generators, not intended to be run long hours or very often.
OPERATING SPEED
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 of a generator depends on a fixed engine speed. To produce 60 Hz electricity, most engines operate at 1800 or 3600 RPM. Each has its advantages and drawbacks. 1800 RPM, four pole sets are the most common and least expensive in large generators. They offer the best balance of noise, efficiency, cost and engine life. 3600 RPM, two pole sets are smaller and lightweight, best suited for portable, light-duty applications. 3600 RPM sets are considered "Standby Generators" and can never be considered for prime power use.
In simple terms it’s like operating your car at 90 mph, versus 45mph – at 45mph your car will last longer, is quieter, less maintenance and longer life. Most 3600 rpm units are twin cylinder air cooled lawn mower engines, while the water cooled 1800 rpm units are comparable to those found in forklift and tractor engines. The bottom line is the 1800 rpm water cooled units will last longer, offer less maintenance problems and be more fuel efficient. In addition, 1800 RPM generators are designed to be rebuilt, 3600 RPM units are designed to replaced and are much lower in cost (most of the time). Some 3600 RPM stationary units and most RV and commercial power units can be rebuilt at least one or more times but this process is not inexpensive.
In simple terms it’s like operating your car at 90 mph, versus 45mph – at 45mph your car will last longer, is quieter, less maintenance and longer life. Most 3600 rpm units are twin cylinder air cooled lawn mower engines, while the water cooled 1800 rpm units are comparable to those found in forklift and tractor engines. The bottom line is the 1800 rpm water cooled units will last longer, offer less maintenance problems and be more fuel efficient. In addition, 1800 RPM generators are designed to be rebuilt, 3600 RPM units are designed to replaced and are much lower in cost (most of the time). Some 3600 RPM stationary units and most RV and commercial power units can be rebuilt at least one or more times but this process is not inexpensive.
FEATURES & BENEFITS TO LOOK FOR
Engine block. For long life and quiet operation we recommend four cycle, liquid cooled, industrial duty diesel engines.
Air or liquid cooling. Air-cooled engines require a tremendous amount of air and may require ducting and they are somewhat noisier. Liquid cooling offers quieter operation, more even temperature control and therefore longer engine life. Modern air cooled engines are suitable for many applications, especially short run, portable or standby uses.
Intake Air. All quality generators have intake air filters with replaceable filter elements. Today even small portables have replaceable air cleaners.
Mufflers. Most generator come equipped with an industrial grade muffler. One good investment is a residential or critical muffler that is much quieter and lasts longer. All enclosed generators should be equipped with at least a residential and preferably a critical muffler.
Lubrication. The lubrication system should have a full flow, spin-on oil filter. Larger generators should have a filter bypass. Most generators today have low oil alarms and shutdowns, make sure the generator you select has this valuable feature, its simply a must have protection.
Major brand of engine. We do not know why people would even consider an inferior "scrap metal" unit or "off brand" engine, you will not be able to obtain the necessary parts, service and support. Many engines come with a box of spare parts including pistons, rings and bearings because your going to need them all. Save yourself some grief and buy a major brand of engine. If you buy a junk engine, we wont service it and most other reputable dealers won't either.
Electrical system and circuit breakers. Standard 12 volt system should include at least the following: 1) Quality starter motor and battery. Larger generators should include a charging alternator with a solid state voltage regulator. 2) Larger diesel units should come with a pre-heat switch and all generators should have a start/stop switch. 3) Al generators should have a safety shutdown system to protect the engine in case of oil pressure loss, generator over-speed or over-crank and high water (or operating) temperature. 4) System circuit breaker to protect the generator. On small systems and portables there should be a circuit breaker on each circuit.
GENERATOR END
(The part that makes the generator "generate" electricity.)
AC generator should have a 4-pole revolving field. An automatic voltage regulator will provide “clean” power. Normal utility power is +/- 6% voltage regulation; most generators are even better ranging from +/- 5% or .25 % and even better. Most modern generators offer AVR – Automatic Voltage Regulation or some other proprietary brand of voltage regulation and can be safely used with modern electronics and computers.
Lifetime lubricated bearing. Cheap generators are not supplied with these bearings. They often require complete disassembly every two or three years for bearing replacement. Most modern power alternators, or generator ends, are provided with industrial quality lifetime lubricated bearings
AC generator should have a 4-pole revolving field. An automatic voltage regulator will provide “clean” power. Normal utility power is +/- 6% voltage regulation; most generators are even better ranging from +/- 5% or .25 % and even better. Most modern generators offer AVR – Automatic Voltage Regulation or some other proprietary brand of voltage regulation and can be safely used with modern electronics and computers.
Lifetime lubricated bearing. Cheap generators are not supplied with these bearings. They often require complete disassembly every two or three years for bearing replacement. Most modern power alternators, or generator ends, are provided with industrial quality lifetime lubricated bearings
ENGINE ACCESSORIES AND CONTROLS
Upon determining the generator size you will need, make a list of optional and installation equipment you require. For noise abatement, we recommend a residential (not industrial grade) muffler. A good primary fuel filter/water separator is a must to protect your engine's fuel system. Stand-by sets may require a block heater to keep the coolant/water mix at an adequate temperature for easier starting and less smoking on startup.
WHAT SIZE SET WILL I NEED?
Sizing is the most important step; nothing is more critical in your choice of a generator. A set that is too small won't last, will smoke and can do damage to your electrical equipment. If it is too large, the engine will carbon up, wet stack or “slobber” and this means excess fuel consumption and early failure. We recommend that a generator set never run continuously with less than 40% load - 50% to 75% is optimum.
Additional factors, which may affect efficient operation of your generator, are high altitude and high air temperature. These conditions will lower generator output. You must take into account your elevation, normal and extremes of temperature and other factors. Ask your sales engineer for de-rating information. Allow three (3) percent loss in efficiency for each 1000 feet above sea level minimum. Check the manufactures specifications and use the de-rating factor they specify. Nothing is worse than buying a generator that is too small.
Additional factors, which may affect efficient operation of your generator, are high altitude and high air temperature. These conditions will lower generator output. You must take into account your elevation, normal and extremes of temperature and other factors. Ask your sales engineer for de-rating information. Allow three (3) percent loss in efficiency for each 1000 feet above sea level minimum. Check the manufactures specifications and use the de-rating factor they specify. Nothing is worse than buying a generator that is too small.
MOTOR STARTING LOADS
In addition to load requirements, it is important to consider motor starting load. We use the rule of thumb that starting a motor requires up to three (3) times more wattage than running loads. Selecting a generator, which is inadequate for your motor starting needs, may make it difficult to start motors in air conditioners, compressors or freezers. In addition, the starting load causes voltage dips, which is why the lights dim when a large motor is started. These voltage dips can be more than annoying – voltage dips can ruin delicate electronic equipment such as computers. You must make sure you account for starting loads, if you cant start the load you can't run it.
GENERATOR INSTALLATION
A detailed installation guide will usually be provided with your generator. Here are some important points to consider when you install your generator.
We strongly recommend that the installation be performed by a licensed electrical or mechanical contractor. They have the tools, the know-how and an understanding of regulations and local codes. Their expertise will save you money in the long run. Should you chose to perform the installation yourself, PLEASE do your homework before tackling the job and obtain the proper permits required by your local jurisdiction. While all GenSets have some basic requirements, each brand and model has unique installation requirements. Also, it is extremely important to have all relative codebooks for reference and to adhere to strictly adhere to the laws which were designed for your safety. Most important of all, your system must be inspected before starting to prevent fires and explosions from improper installation.
We strongly recommend that the installation be performed by a licensed electrical or mechanical contractor. They have the tools, the know-how and an understanding of regulations and local codes. Their expertise will save you money in the long run. Should you chose to perform the installation yourself, PLEASE do your homework before tackling the job and obtain the proper permits required by your local jurisdiction. While all GenSets have some basic requirements, each brand and model has unique installation requirements. Also, it is extremely important to have all relative codebooks for reference and to adhere to strictly adhere to the laws which were designed for your safety. Most important of all, your system must be inspected before starting to prevent fires and explosions from improper installation.
LOCATION
Ensure the following items are considered, read the manual for the generator.
Air inlet for combustion and engine cooling.
Outlets for exhaust and hot cooling air.
Fuel, battery and AC electrical connections.
Remember to monitor for carbon monoxide!
Rigid, level mounting platforms (many sets are already mounted on a steel skid base).
Open accessibility for easy service.
Isolation from living space. Keep noise and exhaust away from occupied areas.
Space and equipment to extinguish a fire. Minimize the possibility of fire danger.
Remember, GenSets move on their vibration mounts. Allow clearance to compensate and use flex-joints on all lines and connections.
Air inlet for combustion and engine cooling.
Outlets for exhaust and hot cooling air.
Fuel, battery and AC electrical connections.
Remember to monitor for carbon monoxide!
Rigid, level mounting platforms (many sets are already mounted on a steel skid base).
Open accessibility for easy service.
Isolation from living space. Keep noise and exhaust away from occupied areas.
Space and equipment to extinguish a fire. Minimize the possibility of fire danger.
Remember, GenSets move on their vibration mounts. Allow clearance to compensate and use flex-joints on all lines and connections.
EXHAUST SYSTEMS
The exhaust system may need to be covered with insulated material to prevent fire resulting from contact with combustible materials. We recommend a heat blanket over exhaust outlets to reduce the heat radiated from the exhaust and to ensure personal safety. Some insulation materials are best left to professionals with the proper equipment. Keep all piping away from combustible materials including walls. A seamless, stainless steel flexible joint must be used between the generator set and the exhaust system to prevent metal fatigue. Do not use the exhaust manifold to support the exhaust system because the weight will cause manifold failure. Exhaust pipe hangers are readily available and inexpensive.
FUEL SYSTEM
Extreme care should be taken in designing and installing the fuel system to prevent fire danger. Fuel lines should have as few connections as possible and be routed to prevent damage. Keep lines away from hot engine or exhaust components. The lines should be no smaller than the inlet and outlet on the engine. Support fuel lines with clamps, as needed, to help prevent metal fatigue from vibration. The fuel tank should be level with or below the set to prevent siphoning in the event of a line failure. Remember to check the lift capacity of the engine fuel pump and stay within its limits. If the set is higher than the tank, an auxiliary fuel pump may be required.
To prevent water ingestion, fuel should be drawn out of the top of the tank with the pick-up extending to no more than two inches from the bottom. Fuel storage tanks must have leakage protection and many jurisdictions require spill basins. Above ground tanks are recommended and cheaper but you must check your local codes before installing a tank. The safest tanks are double walled with alarms. These alarms are simple and well worth the investment to avoid a possible fuel spill, and significant clean-up costs. If the tank is mounted above the generator set, use a fuel shut-off valve, so that you can work on the fuel system without the fuel-siphoning out. It also allows you to cut-off fuel flow in the event of line breakage.
To prevent water ingestion, fuel should be drawn out of the top of the tank with the pick-up extending to no more than two inches from the bottom. Fuel storage tanks must have leakage protection and many jurisdictions require spill basins. Above ground tanks are recommended and cheaper but you must check your local codes before installing a tank. The safest tanks are double walled with alarms. These alarms are simple and well worth the investment to avoid a possible fuel spill, and significant clean-up costs. If the tank is mounted above the generator set, use a fuel shut-off valve, so that you can work on the fuel system without the fuel-siphoning out. It also allows you to cut-off fuel flow in the event of line breakage.
A high quality, fuel/water separator filter should be mounted as close to the generator set as possible. Because of its explosive nature, gasoline fuel systems have special requirements; see your tank supplier for complete information
COMBUSTION AND COOLING AIR
The generator set requires air for combustion and cooling. A radiator and a “pusher” engine fan cool the generator engine temperature. Your car or truck will normally operate with a “puller” fan. An internal fan cools the generator.
OUTDOOR MOUNTING
GenSets that are housed in weather-protective enclosures are designed for installation out-of-doors. Typically a cement pad is placed in a suitable location, out of sight but with easy access for maintenance and fueling. The generator is secured to the pad. Choose a site close to the electric service and fuel supply lines (natural gas, propane, or diesel). The image below shows a typical natural gas installation. The main distribution panel, transfer switch and sub-panels are inside the building in this example, but more often the distribution panel, sub-panels and transfer switch are outside. You should make sure that 110v power is available at the generator for battery charging.
The GenSet must be a minimum of 3 ft from combustible material (NFPA 37). Leave at least 3 ft (or more if the housing and instructions for your particular unit) all around the GenSet enclosure for access to the inside (NEC Art. 110-26a, Art. 110-26b). The GenSet must be at least 5 ft from any opening (window, door, vent, etc.) in a wall, and the exhaust must not be able to accumulate in any occupied area. See figure below.
The GenSet must be a minimum of 3 ft from combustible material (NFPA 37). Leave at least 3 ft (or more if the housing and instructions for your particular unit) all around the GenSet enclosure for access to the inside (NEC Art. 110-26a, Art. 110-26b). The GenSet must be at least 5 ft from any opening (window, door, vent, etc.) in a wall, and the exhaust must not be able to accumulate in any occupied area. See figure below.
INDOOR MOUNTING
We do not recommend locating generator sets indoors in residential applications and small commercial and industrial applications. The primary reason to avoid indoor installation is safety. Carbon monoxide gas is odorless, colorless and can accumulate in closed spaces. You can walk into a room full of carbon monoxide and be overcome. A gas leak in space attached to your home can kill you and your family.
In addition to safety, it costs more to install a GenSet indoors than for the same GenSet provided with the factory weatherproof housing. When a GenSet is installed indoors, the building must be designed carefully to handle ventilation to remove heat and any fumes due to fuel, exhaust, lubrication and starting batteries. The radiator must be provided with a duct adapter that interfaces properly with louvers on an outside wall of the building. Adequate air intake flow must be available not only for the radiator fan but also for cooling the alternator. The engine exhaust piping and muffler must be tight to prevent any leaks that would allow dangerous carbon monoxide to accumulate inside the building.
Generally, the room or space in which the generator operates, should not exceed 100 F. We recommend keeping it under 85 F if possible. Generator installations require an intake of cool, clean air and an outlet vent for hot air. Whenever possible the cool air should be drawn over the alternator (or generator end) to help keep the alternator cool. The size of the space affects the room temperature (the smaller the space the generator runs in, the higher the room temperature is likely to be), smaller spaces may require ducting. The size of the generator and the outside air temperature or climate must be considered. In an indoor installation, increasing these vent sizes may cool the room down to acceptable levels and ensure “positive” airflow. Positive airflow is cool, clean air in and hot air out, as opposed to circulating hot air inside the room. Generator cooling fans move moisture as well as air. Moist air is corrosive to a GenSets copper windings, so make sure air inlets are positioned to minimize moisture intake.
Automatic fire suppression systems may also be required. Check with your local fire codes. You should also contact your fire insurance provider to determine if an indoor GenSet is even permitted.
Installation engineered to meet all the above requirements and all safety codes can still become a hazard later. For an installation to remain safe, it has to be regularly inspected and maintained to ensure that leaks or other dangerous conditions do not develop with age or use. Sites that do not have a knowledgeable maintenance staff trained to support an indoor generator set should not install a unit inside a building.
Another factor is the initial cost. It is impossible to construct a building to house a GenSet at a cost as low as the factory housing that can be ordered with the GenSet. And even if the building already exists, the design expense and costs to adapt it for a generator set installation usually will exceed the enclosure cost available from the GenSet manufacturer. For a small GenSet the cost of an open unit with duct adaptor and exhaust pipe kit is as little as $600 less than the same GenSet with the factory weather housing. The additional costs for just the exhaust thimble and louvers exceed that savings.
Please read Policy, Warranties and Disclaimers. You as the buyer and user of generators sold by GeneratorJoe assume all risk and liability in connection with all equipment purchased
AC CONNECTIONS
Connecting the generator to your electrical distribution system is a job for a qualified, licensed and bonded electrician who is familiar with local building codes. Electricity is dangerous, respect it.
TRANSFER SWITCHES & SWITCHGEAR
All generator systems require a circuit breaker and a distribution panel. The circuit breaker protects the generator set from short circuit and unbalanced electrical loads. The distribution panel divides and routes the connected loads and includes circuit breakers to protect these loads. Stand-by systems also require a main circuit breaker between the utility source and the transfer panel. The transfer panel switches power from the utility to the GenSet and back so that both aren't on at the same time. Residential, commercial and industrial generators are equipped with auto-start to allow connection to auto-transfer switches.
Unless you have no other electric service (utility power), you must install a transfer switch. Normally the transfer switch must be the same size as the service panel or a sub-panel off the service pane. The transfer panel switches power from the utility to the GenSet and back so that both aren't on at the same time. Auto-start, auto-transfer systems are available and are relatively inexpensive. We can help you determine what you need.
Historic developments
Before the connection between magnetism and electricity was discovered, electrostatic generators were invented that used electrostatic principles. These generated very high voltages and low currents. They operated by using moving electrically charged belts, plates and disks to carry charge to a high potential electrode. The charge was generated using either of two mechanisms:
Electrostatic induction
The triboelectric effect, where the contact between two insulators leaves them charged.
Because of their inefficiency and the difficulty of insulating machines producing very high voltages, electrostatic generators had low power ratings and were never used for generation of commercially-significant quantities of electric power. The Wimshurst machine and Van de Graaff generator are examples of these machines that have survived.
Electrostatic induction
The triboelectric effect, where the contact between two insulators leaves them charged.
Because of their inefficiency and the difficulty of insulating machines producing very high voltages, electrostatic generators had low power ratings and were never used for generation of commercially-significant quantities of electric power. The Wimshurst machine and Van de Graaff generator are examples of these machines that have survived.
Jedlik's dynamo
Main article: Jedlik's dynamo
In 1827, Hungarian Anyos Jedlik started experimenting with electromagnetic rotating devices which he called electromagnetic self-rotors. In the prototype of the single-pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic. He formulated the concept of the dynamo at least 6 years before Siemens and Wheatstone but didn't patent it as he thought he wasn't the first to realize this. In essence the concept is that instead of permanent magnets, two electromagnets opposite to each other induce the magnetic field around the rotor. Jedlik's invention was decades ahead of its time.[citation needed]
Faraday's disk
In 1827, Hungarian Anyos Jedlik started experimenting with electromagnetic rotating devices which he called electromagnetic self-rotors. In the prototype of the single-pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic. He formulated the concept of the dynamo at least 6 years before Siemens and Wheatstone but didn't patent it as he thought he wasn't the first to realize this. In essence the concept is that instead of permanent magnets, two electromagnets opposite to each other induce the magnetic field around the rotor. Jedlik's invention was decades ahead of its time.[citation needed]
Faraday's disk
In 1831-1832 Michael Faraday discovered the operating principle of electromagnetic generators. The principle, later called Faraday's law, is that a potential difference is generated between the ends of an electrical conductor that moves perpendicular to a magnetic field. He also built the first electromagnetic generator, called the 'Faraday disc', a type of homopolar generator, using a copper disc rotat
ing between the poles of a horseshoe magnet. It produced a small DC voltage, and large amounts of current.
This design was inefficient due to self-cancelling counterflows of current in regions not under the influence of the magnetic field. While current flow was induced directly underneath the magnet, the current would circulate backwards in regions outside the influence of the magnetic field. This counterflow limits the power output to the pickup wires, and induces waste heating of the copper disc. Later homopolar generators would solve this problem by using an array of magnets arranged around the disc perimeter to maintain a steady field effect in one current-flow direction.
Another disadvantage was that the output voltage was very low, due to the single current path through the magnetic flux. Experimenters found that using multiple turns of wire in a coil could produce higher more useful voltages. Since the output voltage is proportional to the number of turns, generators could be easily designed to produce any desired voltage by varying the number of turns. Wire windings became a basic feature of all subsequent generator designs.
However, recent advances (rare earth magnets) have made possible homo-polar motors with the magnets on the rotor, which should offer many advantages to older designs.
ing between the poles of a horseshoe magnet. It produced a small DC voltage, and large amounts of current.This design was inefficient due to self-cancelling counterflows of current in regions not under the influence of the magnetic field. While current flow was induced directly underneath the magnet, the current would circulate backwards in regions outside the influence of the magnetic field. This counterflow limits the power output to the pickup wires, and induces waste heating of the copper disc. Later homopolar generators would solve this problem by using an array of magnets arranged around the disc perimeter to maintain a steady field effect in one current-flow direction.
Another disadvantage was that the output voltage was very low, due to the single current path through the magnetic flux. Experimenters found that using multiple turns of wire in a coil could produce higher more useful voltages. Since the output voltage is proportional to the number of turns, generators could be easily designed to produce any desired voltage by varying the number of turns. Wire windings became a basic feature of all subsequent generator designs.
However, recent advances (rare earth magnets) have made possible homo-polar motors with the magnets on the rotor, which should offer many advantages to older designs.
Dynamo
Main article: Dynamo
Dynamos are no longer used for power generation due to the size and complexity of the commutator needed for high power applications. This large belt-driven high-current dynamo produced 310 amperes at 7 volts, or 2,170 watts, when spinning at 1400 RPM.
Dynamo Electric Machine [End View, Partly Section] (U.S. Patent 284,110)
The first Turbogenerator Designed by the Hungarian engineer Ottó Bláthy in 1903
This content has an uncertain copyright status and is pending deletion. You can comment on its removal.
The Dynamo was the first electrical generator capable of delivering power for industry. The dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator. The first dynamo was built by Hippolyte Pixii in 1832.
Through a series of accidental discoveries, the dynamo became the source of many later inventions, including the DC electric motor, the AC alternator, the AC synchronous motor, and the rotary converter.
A dynamo machine consists of a stationary structure, which pr
ovides a constant magnetic field, and a set of rotating windings which turn within that field. On small machines the constant magnetic field may be provided by one or more permanent magnets; larger machines have the constant magnetic field provided by one or more electromagnets, which are usually called field coils.
Large power generation dynamos are now rarely seen due to the now nearly universal use of alternating current for power distribution and solid state electronic AC to DC power conversion. But before the principles of AC were discovered, very large direct-current dynamos were the only means of power generation and distribution. Now power generation dynamos are mostly a curiosity.
Dynamos are no longer used for power generation due to the size and complexity of the commutator needed for high power applications. This large belt-driven high-current dynamo produced 310 amperes at 7 volts, or 2,170 watts, when spinning at 1400 RPM.
Dynamo Electric Machine [End View, Partly Section] (U.S. Patent 284,110)
The first Turbogenerator Designed by the Hungarian engineer Ottó Bláthy in 1903
This content has an uncertain copyright status and is pending deletion. You can comment on its removal.
The Dynamo was the first electrical generator capable of delivering power for industry. The dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator. The first dynamo was built by Hippolyte Pixii in 1832.
Through a series of accidental discoveries, the dynamo became the source of many later inventions, including the DC electric motor, the AC alternator, the AC synchronous motor, and the rotary converter.
A dynamo machine consists of a stationary structure, which pr
ovides a constant magnetic field, and a set of rotating windings which turn within that field. On small machines the constant magnetic field may be provided by one or more permanent magnets; larger machines have the constant magnetic field provided by one or more electromagnets, which are usually called field coils.Large power generation dynamos are now rarely seen due to the now nearly universal use of alternating current for power distribution and solid state electronic AC to DC power conversion. But before the principles of AC were discovered, very large direct-current dynamos were the only means of power generation and distribution. Now power generation dynamos are mostly a curiosity.
Other rotating electromagnetic generators
Without a commutator, the dynamo is an example of an alternator, which is a synchronous singly-fed generator. With an electromechanical commutator, the dynamo is a classical direct current (DC) generator. The alternator must always operate at a constant speed that is precisely synchronized to the electrical frequency of the power grid for non-destructive operation. The DC generator can operate at any speed within mechanical limits but always outputs a direct current waveform.
Other types of generators, such as the asynchronous or induction singly-fed generator, the doubly-fed generator, or the brushless wound-rotor doubly-fed generator, do not incorporate permanent magnets or field windings (i.e, electromagnets) that establish a constant magnetic field, and as a result, are seeing success in variable speed constant frequency applications, such as wind turbines or other renewable energy technologies.
The full output performance of any generator can be optimized with electronic control but only the doubly-fed generators or the brushless wound-rotor doubly-fed generator incorporate electronic control with power ratings that are substantially less than the power output of the generator under control, which by itself offer cost, reliability and efficiency benefits.
Other types of generators, such as the asynchronous or induction singly-fed generator, the doubly-fed generator, or the brushless wound-rotor doubly-fed generator, do not incorporate permanent magnets or field windings (i.e, electromagnets) that establish a constant magnetic field, and as a result, are seeing success in variable speed constant frequency applications, such as wind turbines or other renewable energy technologies.
The full output performance of any generator can be optimized with electronic control but only the doubly-fed generators or the brushless wound-rotor doubly-fed generator incorporate electronic control with power ratings that are substantially less than the power output of the generator under control, which by itself offer cost, reliability and efficiency benefits.
MHD generator
A magnetohydrodynamic generator directly extracts electric power from moving hot gases through a magnetic field, without the use of rotating electromagnetic machinery. MHD generators were originally developed because the output of a plasma MHD generator is a flame, well able to heat the boilers of a steam power plant. The first practical design was the AVCO Mk. 25, developed in 1965. The U.S. government funded substantial development, culminating in a 25MW demonstration plant in 1987. In the Soviet Union from 1972 until the late 1980s, the MHD plant U 25 was in regular commercial operation on the Moscow power system with a rating of 25 MW, the largest MHD plant rating in the world at that time. [1] MHD generators operated as a topping cycle are currently (2007) less efficient than combined-cycle gas turbines.
Terminology
The two main parts of a generator or motor can be described in either mechanical or electrical terms[citation needed]:
Mechanical:
Rotor: The rotating part of an alternator, generator, dynamo or motor.
Stator: The stationary part of an alternator, generator, dynamo or motor.
Electrical:
Armature: The power-producing component of an alternator, generator, dynamo or motor. In a generator, alternator, or dynamo the armature windings generate the electrical current. The armature can be on either the rotor or the stator.
Field: The magnetic field component of an alternator, generator, dynamo or motor. The magnetic field of the dynamo or alternator can be provided by either electromagnets or permanent magnets mounted on either the rotor or the stator. (For a more technical discussion, refer to the Field coil article.)
Because power transferred into the field circuit is much less than in the armature circuit, AC generators nearly always have the field winding on the rotor and the stator as the armature winding. Only a small amount of field current must be transferred to the moving rotor, using slip rings. Direct current machines necessarily have the commutator on the rotating shaft, so the armature winding is on the rotor of the machine.
The two main parts of a generator or motor can be described in either mechanical or electrical terms[citation needed]:
Mechanical:
Rotor: The rotating part of an alternator, generator, dynamo or motor.
Stator: The stationary part of an alternator, generator, dynamo or motor.
Electrical:
Armature: The power-producing component of an alternator, generator, dynamo or motor. In a generator, alternator, or dynamo the armature windings generate the electrical current. The armature can be on either the rotor or the stator.
Field: The magnetic field component of an alternator, generator, dynamo or motor. The magnetic field of the dynamo or alternator can be provided by either electromagnets or permanent magnets mounted on either the rotor or the stator. (For a more technical discussion, refer to the Field coil article.)
Because power transferred into the field circuit is much less than in the armature circuit, AC generators nearly always have the field winding on the rotor and the stator as the armature winding. Only a small amount of field current must be transferred to the moving rotor, using slip rings. Direct current machines necessarily have the commutator on the rotating shaft, so the armature winding is on the rotor of the machine.
Excitation
Main article: Excitation (magnetic)
An electric genera
tor or electric motor that uses field coils rather than permanent magnets will require a current flow to be present in the field coils for the device to be able to work. If the field coils are not powered, the rotor in a generator can spin without producing any usable electrical energy, while the rotor of a motor may not spin at all. Very large power station generators often utilize a separate smaller generator to excite the field coils of the larger.
In the event of a severe widespread power outage where islanding of power stations has occurred, the stations may need to perform a black start to excite the fields of their largest generators, in order to restore customer power service.
An electric genera
tor or electric motor that uses field coils rather than permanent magnets will require a current flow to be present in the field coils for the device to be able to work. If the field coils are not powered, the rotor in a generator can spin without producing any usable electrical energy, while the rotor of a motor may not spin at all. Very large power station generators often utilize a separate smaller generator to excite the field coils of the larger.In the event of a severe widespread power outage where islanding of power stations has occurred, the stations may need to perform a black start to excite the fields of their largest generators, in order to restore customer power service.
Equivalent circuit
Equivalent circuit of generator and load.G = generatorVG=generator open-circuit voltageRG=generator internal resistanceVL=generator on-load voltageRL=load resistance
The equivalent circuit of a generator and load is shown in the diagram to the right. To determine the generator's VG and RG parameters, follow this procedure: -
Before starting the generator, measure the resistance across its terminals using an ohmmeter. This is its DC internal resistance RGDC.
Start the generator. Before connecting the load RL, measure the voltage across the generator's terminals. This is the open-circuit voltage VG.
Connect the load as shown in the diagram, and measure the voltage across it with the generator running. This is the on-load voltage VL.
Measure the load resistance RL, if you don't already know it.
Calculate the generator's AC internal resistance RGAC from the following formula:
Note 1: The AC internal resistance of the generator when running is generally slightly higher than its DC resistance when idle. The above procedure allows you to measure both values. For rough calculations, you can omit the measurement of RGAC and assume that RGAC and RGDC are equal.
Note 2: If the generator is an AC type, use an AC voltmeter for the voltage measurements.
The maximum power theorem states that the maximum power can be obtained from the generator by making the resistance of the load equal to that of the generator. This is inefficient since half the power is wasted in the generator's internal resistance; practical electric power generators operate with load resistance much higher than internal resistance, so the efficiency is greater.
Vehicle-mounted generators
Early motor vehicles until about the 1960s tended to use DC generators with electromechanical regulators. These have now been replaced by alternators with built-in rectifier circuits, which are less costly and lighter for equivalent output. Automotive alternators power the electrical systems on the vehicle and recharge the battery after starting. Rated output will typically be in the range 50-100 A at 12 V, depending on the designed electrical load within the vehicle. Some cars now have electrically-powered steering assistance and air conditioning, which places a high load on the electrical system. Large commercial vehicles are more likely to use 24 V to give sufficient power at the starter motor to turn over a large diesel engine. Vehicle alternators do not use permanent magnets and are typically only 50-60% efficient over a wide speed range.[2] Motorcycle alternators often use permanent magnet stators made with rare earth magnets, since they can be made smaller and lighter than other types. See also hybrid vehicle.
Some of the smallest generators commonly found power bicycle lights. These tend to be 0.5 ampere, permanent-magnet alternators supplying 3-6 W at 6 V or 12 V. Being powered by the rider, efficiency is at a premium, so these may incorporate rare-earth magnets and are designed and manufactured with great precision. Nevertheless, the maximum efficiency is only around 80% for the best of these generators - 60% is more typical - due in part to the rolling friction at the tire-generator interface from poor alignment, the small size of the generator, bearing losses and cheap design.
Sailing yachts may use a water or wind powered generator to trickle-charge the batteries. A small propeller, wind turbine or impeller is connected to a low-power alternator and rectifier to supply currents of up to 12 A at typical cruising speeds.
Engine-generator
Main article: Engine-generator
An engine-generator is the combination of an electrical generator and an engine (prime mover) mounted together to form a single piece of self-contained equipment. The engines used are usually piston engines, but gas turbines can also be used. Many different versions are available - ranging from very small portable petrol powered sets to large turbine installations.
Human powered electrical generators
Main article: Self-powered equipment
A generator can also be driven by human muscle power (for instance, in field radio station equipment).
Human powered direct current generators are commercially available, and have been the project of some DIY enthusiasts. Typically operated by means of pedal power, a converted bicycle trainer, or a foot pump, such generators can be practically used to charge batteries, and in some cases are designed with an integral inverter. The average adult could generate about 125-200 watts on a pedal powered generator. Portable radio receivers with a crank are made to reduce battery purchase requirements, see clockwork radio.
Before starting the generator, measure the resistance across its terminals using an ohmmeter. This is its DC internal resistance RGDC.
Start the generator. Before connecting the load RL, measure the voltage across the generator's terminals. This is the open-circuit voltage VG.
Connect the load as shown in the diagram, and measure the voltage across it with the generator running. This is the on-load voltage VL.
Measure the load resistance RL, if you don't already know it.
Calculate the generator's AC internal resistance RGAC from the following formula:
Note 1: The AC internal resistance of the generator when running is generally slightly higher than its DC resistance when idle. The above procedure allows you to measure both values. For rough calculations, you can omit the measurement of RGAC and assume that RGAC and RGDC are equal.
Note 2: If the generator is an AC type, use an AC voltmeter for the voltage measurements.
The maximum power theorem states that the maximum power can be obtained from the generator by making the resistance of the load equal to that of the generator. This is inefficient since half the power is wasted in the generator's internal resistance; practical electric power generators operate with load resistance much higher than internal resistance, so the efficiency is greater.
Vehicle-mounted generators
Early motor vehicles until about the 1960s tended to use DC generators with electromechanical regulators. These have now been replaced by alternators with built-in rectifier circuits, which are less costly and lighter for equivalent output. Automotive alternators power the electrical systems on the vehicle and recharge the battery after starting. Rated output will typically be in the range 50-100 A at 12 V, depending on the designed electrical load within the vehicle. Some cars now have electrically-powered steering assistance and air conditioning, which places a high load on the electrical system. Large commercial vehicles are more likely to use 24 V to give sufficient power at the starter motor to turn over a large diesel engine. Vehicle alternators do not use permanent magnets and are typically only 50-60% efficient over a wide speed range.[2] Motorcycle alternators often use permanent magnet stators made with rare earth magnets, since they can be made smaller and lighter than other types. See also hybrid vehicle.
Some of the smallest generators commonly found power bicycle lights. These tend to be 0.5 ampere, permanent-magnet alternators supplying 3-6 W at 6 V or 12 V. Being powered by the rider, efficiency is at a premium, so these may incorporate rare-earth magnets and are designed and manufactured with great precision. Nevertheless, the maximum efficiency is only around 80% for the best of these generators - 60% is more typical - due in part to the rolling friction at the tire-generator interface from poor alignment, the small size of the generator, bearing losses and cheap design.
Sailing yachts may use a water or wind powered generator to trickle-charge the batteries. A small propeller, wind turbine or impeller is connected to a low-power alternator and rectifier to supply currents of up to 12 A at typical cruising speeds.
Engine-generator
Main article: Engine-generator
An engine-generator is the combination of an electrical generator and an engine (prime mover) mounted together to form a single piece of self-contained equipment. The engines used are usually piston engines, but gas turbines can also be used. Many different versions are available - ranging from very small portable petrol powered sets to large turbine installations.
Human powered electrical generators
Main article: Self-powered equipment
A generator can also be driven by human muscle power (for instance, in field radio station equipment).
Human powered direct current generators are commercially available, and have been the project of some DIY enthusiasts. Typically operated by means of pedal power, a converted bicycle trainer, or a foot pump, such generators can be practically used to charge batteries, and in some cases are designed with an integral inverter. The average adult could generate about 125-200 watts on a pedal powered generator. Portable radio receivers with a crank are made to reduce battery purchase requirements, see clockwork radio.
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