jim rozen wrote:

have to use the correct voltage when figuring
I x V x cos(angle).

He said he had measured the current (11A) so presumably he has a clip on
ammeter. He also said, IIRC, he has a multimeter so can measure the
voltage across the motor. With the arrangement I suggested, he can
measure the time between zero crossings of the waveforms, dT. Then
angle=360*dT/16.7msec and we know V, I and angle. So
P=V x I x Cos(angle).

Ted