Electric motor efficiency calculation

[Nevalite]

Hello everyone,

I am trying to calculate the electric efficiency of some 3 phase electric motors but I am a little confused about the power factor.

efficiency=work out/work in

work out=rated W of my motor (hp*745.7)

work in= V*A*PF*√3

Is the work in correct?

Thanks

 

[Windadct]

Your formula is for POWER. Work is Power * time. Balanced 3 phase P = V*A*PF*√3.

Work = Energy = P*T ( You pay for Kilowatt Hours - not Kilowatts)

However the trick in this type of project is typically accurately measuring the mechanical output - needing a calibrated dyno - or other device.

Also - for efficiency it is important (or more meaningful) to define what the operating point is for the efficiency calculation / measurements. --e.g. A Cold motor is more efficient then a warm motor - etc.