PFC for Motors
The capacitor output should be approx. 90% of the apparent power of the motor when idle. This means a power factor of 0.9% at full load and 0.95 … 0.98 during idling. Important: The capacitor output must not be rated too high for individual compensated machines where the capacitor is directly con- nected with the motor clamp. This especially applies when the machine has a big oscillating weight and still continues to rotate after switching off.
The capacitor placed in parallel may act as generator for the motor which will cause serious overvoltages. The consequence could be heavy damage to the capacitor as well as to the motor.