example, I have a 10hp. 3 phase motor that has a full load amper of 28 amps, so what's the amount of kilowatts that use per one hour of operation and what's the formula to calculate?
thanks for any imput.
2007-04-29 03:44:24 · 3 answers · asked by hector596 2 in Science & Mathematics ➔ Engineering
The first huge assumption is that the motor is actually doing 10 HP worth of work. Most motors have been sized for "worst case conditions" that rarely occur and then add some extra capacity "just in case".
For arguments sake, let's assume that the load on the motor's shaft requires an input of 10 HP.
The conversion factor you're looking for is 1 HP = .746 kW.
10 HP = 7.46 kW. Operating for one hour is 7.46 kWh.
Notice that to compute the power consumption we did not need to know the voltage, the amperage, and didn't care whether it as a 1-phase or 3-phase motor.
The 28 amp value you quoted is either off the nameplate or was computed by an electrician. This value has used a conversion factor of 1 HP = 1 kVA. This is a substantial increase from 1 HP = .746 kW.
.208 kV x 28 A x √3 = 10 kVA
2007-04-29 10:46:41 · answer #1 · answered by Thomas C 6 · 0⤊ 0⤋
Actually, if you have the horsePOWER rating you don't really need to know either the voltage or the current, you would however need to know the efficiency, a horsepower is by definition very close to 750wats (I don't remember the exact number, it's a trifle less) For a ball park figure I'd call it 800 or 900wats per horsepower, or 8 or 9 kW total, but that is only an estimate since I don't know the efficiency.
2007-04-29 10:57:31 · answer #2 · answered by tinkertailorcandlestickmaker 7 · 0⤊ 0⤋
You also have to know the voltage... Volts x amps = watts. Divide by 1000 to get kW.
2007-04-29 10:48:37 · answer #3 · answered by Gene 7 · 0⤊ 1⤋