The following information is found on a motor nameplate:
HP = 3/4
voltage = 120/240
freq = 60Hz
RPM = 3450
KVA = 1.0
PF = .75
Amps
Eff. = 75%

Calculate the watts used if the motor is operating at 240 volts...

here is the math I used

PF = True Power / Apparent Power
.75=W/1000
W=750
A=W/V
A=750/240
A=3.125

Is this the correct calculation?

Also, I believe the efficiency is the ratio of the power in to the power out of the motor. When does this have to be accounted for in calculations? And how do you measure the power out of the motor? Power in would obviously be watts, but wouldnt the power out be somthing having to do with spinning a shaft such as work, or torque?

Thanks

 

or should it be like so..?

A=VA/V=1000/240=4.16

W=V*A*PF = 240*4.16*.75 = 748