Testing motors OFF Line that have PFCC (Power Factor Correction Capacitors)

Motors that have PFCC (Power Factor Correction Capacitors) wired into the motor circuit can be very dangerous!

Description/Definition: PFCC (Power Factor Correction Capacitors) Induction electrical equipment takes more power from the electrical supply system than is necessary to produce the work required. Power factor is a term used to describe or measure the amount of energy needed by an electrical induction system to establish the magnetic fields that enable the motor to do work. Power factor is defined as the ratio of the true power used in an electrical circuit, to the power which is apparently being drawn from the source.
Power Factor Correction Capacitors are used on motors to correct the power factor. A properly sized capacitor will offset most of the lagging current of a motor and raise its power factor to about 95%.

If the capacitors do not discharge properly, the potential for an electrical shock is there. These capacitors wires coming to the starter are not very large, and sometimes difficult to recognize especially in an under lit area. Always conduct your plants lockout procedure and confirm again no power present. Always discharge the capacitors with your plants procedure, and then separate the capacitor circuit from the motor circuit. Take an OFF LINE test and save results for evaluation of the health of the motor. Know since you have PFCC (Power Factor Correction Capacitors) wired into the motor circuit you need to check the PFCC. Test the in line fuses to capacitors, test the discharging resistor, inspect visually the capacitor enclosure for any abnormalities and then test capacitors for stated rating that on name plate. PFCC (Power Factor Correction Capacitors) can save about 60% on a utility bill for the motor. Our managers are worried about turning off lights and fans, but the real savings is maintaining your PFCC (Power Factor Correction Capacitors). I suggest creating a PM in your RCM software and keep them up that way.

Reader tip provided by Dave Humphrey
Technology Group Electrician
Allison Transmission
Anderson Indiana

Thanks Dave - your stainless steel - diamond plate - Reliabilityweb.com coffee mug is on the way.

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