FLA for 1000 HP motor
FLA for 1000 HP motor
(OP)
The NEC gives the full load currents for motors up to 500 HP. Do we extrapolate for larger machines?
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RE: FLA for 1000 HP motor
RE: FLA for 1000 HP motor
Yes, extrapolation is a way to get it when you do not have nameplate data. Another way is assuming the motor Efficiency (EFF) and Power factor (PF).
For your specific motor, at full load; EFF~0.93 and PF~0.87, and for 4000 VL.
IFL ~= 1000*746/(1.732*4000*0.93*0.87)= 133 Amperes.
RE: FLA for 1000 HP motor
RE: FLA for 1000 HP motor
Thanks for the reminder
RE: FLA for 1000 HP motor
Pardon me, I assumed.
RE: FLA for 1000 HP motor
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RE: FLA for 1000 HP motor
RE: FLA for 1000 HP motor
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RE: FLA for 1000 HP motor
RE: FLA for 1000 HP motor
The full load amps depends on many factors beside horsepower, including motor speed, motor voltage, motor design type, specified efficiency, etc. Low speed motors can have significantly higher amp requirements due to lower power factor.
And none of this applies to submersible motors - I don't even trust the NEC tables for those.
RE: FLA for 1000 HP motor
I had assumed that the NEC anticipated a possible future motor replacement with a less efficient motor and made allowances in the tables. That is, if a high efficiency motor was to be replaced with a normal efficiency motor, the ampacity of the circuit will still be adequate.
respectfully