Single phase motor problem

Feb 10, 2004 2 Replies

I have an old single phase 110V 5.6amp 1/3HP 1200rpm induction motor that operates a scroll saw..The motor ran well in the past but now it won't start, it just sits there drawing current. If I spin the motor by quickly moving the belt it will start.



It has capacitor start and the cap measures 84 mfd. I'm assuming the cap is OK because I can read the value with my capacitance meter. I can't read the cap rating printed on the cap clearly but it looks like its a nominal rating of 72 mfd. Is this reasonable?



Is there a centrifugal switch that switches out the capacitor when it starts running?



Any other ideas what the problem could be?


The centrifugal switch should be in the back of the motor. Check to see if there is a small cover that will give you access to it. The contacts are probably pitted and need cleaning. They are not making contact, and so the starting winding is not engaging to give the motor direction.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required