Need help calculating full load power

Thread Starter


Joined Oct 24, 2008
I need to calculate the motor nameplate full load power of a 3 phase delta connected motor in order to set up a new power monitor. These are the specs I have:

HP (full load): 20
Amps (full load): 22.3
motor nameplate voltage: 460
motor nameplate hertz: 60
Control volts from transformer between motor & power phases: 110 VAC
RPM: 3520
RPM (full load): 3519
Power Factor (full load): 91.7%
Efficiency (full load): 91.7
Full Load Torque: 100%, 29.8 lb.-ft.
Duty: Continuous
Stator Res. @ 25 deg C (between lines): .521 Ohms


Joined Feb 4, 2008
Convert HP into watts and then multiply then divide them by the efficiency (but in 0.917 form and not in percent form) to get the active power delivered to the motor from the power supply.