Electrical motors present special electrical startup considerations. They can require up to three times their rated running wattage to start. Motor nameplates generally will show starting watts, some as high as nine times the running wattage. Check the nameplate to be sure. Be certain to use the starting watts when figuring the correct electrical load requirements. If you don't have enough power to start you won't have enough to run. Motor load requirements are listed below: Motor Rating HP | Approximate Running Watts | Universal Motors Small Appliance | Reduction Induction Motors | Capacitor Motors | 1/8 | 275 | 400 | 600 | 850 | 1/4 | 400 | 500 | 850 | 1050 | 1/3 | 450 | 600 | 975 | 1350 | 1/2 | 600 | 750 | 1300 | 1800 | 3/4 | 850 | 1000 | 1900 | 2600 | 1 | 1000 | 1250 | 2300 | 3000 | 1-1/2 | 1600 | 1750 | 3200 | 4200 | 2 | 2000 | 2350 | 3900 | 5100 | 3** | 3000 | 3550 | 5200 | 6800 | ** Motors of higher HP are not generally used. |
WATER WELL PUMP kW / kVA REQUIREMENTS Pump Rating | Externally Regulated Generator | Internally Regulated Generator | HP | Min. kW | Min. kVA | Min. kW | Min. kVA | 1/3 | 1.5 | 1.9 | 1.2 | 1.5 | 1/2 | 2.0 | 2.5 | 1.5 | 1.9 | 3/4 | 3.0 | 3.8 | 2.0 | 2.5 | 1 | 4.0 | 5.0 | 2.5 | 3.125 | 1-1/2 | 5.0 | 6.25 | 3.0 | 3.8 | 2 | 7.5 | 9.4 | 4.0 | 5.0 | 3 | 10.0 | 12.5 | 5.0 | 6.25 | 5 | 15.0 | 18.75 | 7.5 | 9.4 | 7 1/2 | 20.0 | 25.0 | 10.5 | 12.5 | 10 | 30.0 | 37.5 | 15.0 | 18.8 |
NOTES: To avoid damage to your motor or pump, it is recommended that the generator be started and permitted to come up to voltage before the pump or motor is turned on. - A majority of industrial generators are externally regulated. Generators must be sized to deliver at least 65% of the rated voltage during motor starting to ensure adequate motor starting torque.
- Industrial generators typically produce 300+ percent of rated capacity for 15-20 seconds during electrical surges.
- To convert KW into watts multiply KW (x) 1000
NEMA CODES FOR STARTING KVA/hp THREE PHASE MOTORS CODE | STARTING KVA / HP | TYPICAL SIZE RANGE | CODE | STARTING KVA / HP | TYPICAL RANGE | A | 0 - 3.15 | -- | L | 9.0 -10.0 | 1 HP | B | 3.15 - 3.55 | -- | M | 10.0 - 11.2 | Less than 1 HP | C | 3.55 - 4.0 | -- | N | 11.2 - 12.5 | -- | D | 4.0 - 4.5 | -- | P | 12.5 - 14.0 | -- | E | 4.5 - 5.0 | -- | R | 14.0 - 16.0 | -- | F | 5.0 -5.6 | 15 HP and up | S | 16.0 - 18.0 | -- | G | 5.6 - 6.3 | 10 HP | T | 18.0 - 20.0 | -- | H | 6.3 - 7.1 | 7.5 and 5 HP | U | 20.0 - 22.4 | -- | J | 7.1 - 8.0 | 3 HP | V | 22.4 and up | -- | K | 8.0 - 9.0 | 2 and 1-1/2 | | | |
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