Q. Why are run capacitors used on compressors and psc motors? If a Copeland cr32k6-pfv-870 compressor uses a p291-3504, how would it affect the compressor if we gave to them a p291-3004 or p291-4004? Would it also shorten the life of the compressor? ~Jerry Wayne Sams, Comfort Products

A. Thanks for the question, Jerry. This answer is from one of our electrical trainers. This is also something we cover when we train Totaline counter salespeople at Totaline University.

Run capacitors are designed for continuous duty, and the entire time the motor
is running they are energized. Run capacitors are rated in a range of 3–70
microfarads (μF), with voltage classifications of 370 V or 440 V. Single phase
electric motors need a capacitor to energize a second-phase winding. If you use
the wrong run capacitor, the motor will have an uneven magnetic field, and this
will cause the rotor to hesitate at those spots that are uneven. This hesitation can
cause a number of things to happen - the motor can become noisy, increased
energy consumption, it can cause performance to drop, and it is possible the
motor may overheat. However, a motor will not be ruined just because a run
capacitor is faulty. You can substitute a run capacitor with a capacitor of equal
or greater voltage rating and plus or minus 20% of the microfarad rating.

James.Flynn@totaline.com

Jim Flynn
Totaline Marketing and Training Manager

JIM'S TIPS

You saw the cover. You saw the ad. You might be wondering what’s up with our 2011 FREE STUFF program that’s SO BIG. We’d love to tell you and we will... next month. For now, we’ll give you a few hints for what we think is going to be the most gigantic thing to happen at Totaline® sales centers since the FREE STUFF program began.