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Main & Start Winding


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hi i have a capacitor start sp motor i belive they call it psc, which has 2 windings & 1 capacitor(no centrifugal switch) it is 4 pole. i have 4 wires sticking out 2 are for the main winding & 2 are for the start winding. i have paired up the two windings but the problem is how do i find out which pair is start & which pair is main. will one winding have a higher reisistance than the other i seem to remember that from collage can any on help please. (this motor runs a fan)
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Hello Ilmasto, and welcome to the Forum.


I've never considered the issue of winding resistance before, and I thank you for bring your question to the Forum. It gave me an opportunity to do some research on single-phase motors and to add to my personal knowledge.


To find an answer to your question, I contacted the engineering department of a local (USA) AC motor manufacturer with whom I have a good working relationship.


Here is their reply to your question.

"Based on a fixed ... voltage PSC 4 lead design, the
(wdg) resistance will be a higher resistance than the
(wdg). The percentage will vary depending upon the design but you could expect the aux running at least 300-400% above the main, even higher, in some cases, depending upon the design."


Kind regards,

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