Thanks Scotty. BTW, do you really wear red ballerina tutus?
That looks like a cool formula, except that I've never seen a motor nameplate that gives me torque.
waross (Electrical) 23 Apr 09 21:38
"How about using the V/H ratio. Use the amps on the VFD display.
Use the ratio of the output frequency over the rated frequency times the rated voltage to determine the voltage to use in the power formula.
In the example given the voltage would be...
David - thanks for the response. For now, I'm just doing some rough estimating. For volts, I used the voltage available from the MCC. For Amps, I used the read-out on the VFD. For efficiency and pf, I estimated 88% and 90% respectively, which were the lowest values I felt might be in the...
In the past, I've always used the following formula to estimate the BHP being produced by a three-phase motor:
Watts = volts x amps x 1.73 x motor eff x power factor
However, in running this calculation on a particular motor that's operating at 30Hz (half speed), the answer I'm getting appears...
