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bluefitness 12-31-2009 09:54 PM

PTC Starting Devices
Can someone explain how the newer compressors run? They seem to use PTC devices to start the compressor.

Part Details - GE 5sp overload/ptc, part number: AP3796513

It has been a long time, since I went to trade school. I remember being able to just flip over a start relay to check it for continuity. The PTC devices are solid state. I don't even remember domestic refrigerators utilizing run caps. Is the capacitor mounted on the back for starting or a run cap? Do PTC devices fully drop out the start winding, or does it utilize the run cap through the start winding like a PSC motor?

One more thing, a PSC compressor will not start and run without the run cap. I was reading a thread where some techs will use the 3 n 1 and not add the run cap. This causes extra strain on the windings, but the compressor will still run. Sorry for all the questions.

bluefitness 01-01-2010 07:30 AM

I'll try to clarify my initial post. I know how PTC devices work with starting device with start cap inline (superboost or 3 n 1). They drop out the start cap completely. It seems like these new compressors are now using PTC devices to start compressor, but they allow current through the run cap after startup. I believe it is a run cap in the device I am trying to order. It is only a 15mfd capacitor. Can someone enlighten me on how exactly this device utilizes the run cap?

bluefitness 01-04-2010 08:09 AM

Does this part utilize the capacitor as a start cap or a run cap?

richappy 01-04-2010 04:08 PM

The run capacitor sends a small current to the start winding to increase the running torq and prevent compressor stall during brownouts.
Never use a 3n1 start device on the newer 1/5 hp compressors, will burn them out.

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