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Re: convert horsepower to amps If you are looking for a simple unit conversion, you can use this: HP times 746, divided by efficiency, then divided by voltage. Example, for a 460V, 10 HP motor with an efficiency of 85%: { (10 HP) x (746 Watts/HP) } / { .85 efficiency) x (460V) } = 19.08 amps. If you are looking for a basis for sizing conductors ...
AC Electric Motor FLA to HP Calculator. Voltage: Full Load Amps: Efficiency: True continuous Watts: True continuous HP rating: (rounded to 3 decimal places) Note: Most motors are rated using "Peak HP consumed" which is much higher than "true continuous HP".
This is how I would come up with my answer. 1.When I figure 3 phase motors that are squirrel cage and wound-rotor motors any thing over 200 hp I take x 1.2 So 700 x 1.2 = 840 amps 2. 3 phase synchronousmotors (unity power factor) I almost go 1 amp per hp. I get this information from a company whom builds motors for me.
He wants to just increase the size of the breaker. NEC 2008 Table 430.248 tells me a 5 HP motor draws 28 amps Table 430.52 tells me the max Short-Circuit protection is 250% of 28 amps or 70 amps max breaker Table 310.16 tells me #12 can handle 25 - 30 amps depending on the insulation. I know I can size the breaker more that the current carrying ...
1 HP=746 Watts regardless of single phase or three phase. In many cases though the HP is the mechanical output, not the electrical input which must be greater since the motor must be less than 100% efficient. As a rough estimate I would add about 10% to the output in order to estimate the input.
The table Amps is 54A. So 54 x 115%= 62.1A. Can you go down to a 60A or go up to a 100A Nonfusible disconnect General duty safety switch. If it is a single motor then it has to be sized at 115% of the FLA of the motor per table 430.250. A 100A switch is compliant. 430.6 Ampacity and Motor Rating Determination.
Per NEC section 430.62, the first thing you need to figure out is the largest breaker that would be permitted for the largest motor. For an inverse-time circuit breaker serving the 20 horsepower motor, this would be 27 amps x 2.5 = 67.5 amps, rounded up to 70 amps (see NEC section 430.52(C)(1)).
100 HP @ 480 is 124 amps per Table 430.250 Conductor size is 124 times 125%=155 amp. This would be 2/0 @ 75 degree. Max OC device per 430.52 = 124 times 175% for dual element fuses. This would be 217 amp. Next size up = 225 amp. If this is just a garden variety motor and it is not a hard starting load the 200 amp fuses will probably be fine.
It seems unrealistic to base wire/OCP sizing for a 40hp motor using the 172 amps which is characteristic of a 60hp motor...doesn't make sense. Also, we typically would not have the 172 motor amps, 4 control amps and the 176 total amps available to us since the elevator vendor is selected during construction and not design phase.
Apr 24, 2010. #4. Full load amps is what the motor will draw at its rated voltage, speed, frequency and horsepower. change any of these and your amperage will now be running amps. Running amps can be the same as full load amps but the conditions of the power source and load determine the actual amps and are almost never the same as the ...