Lathe Motor Problem

[vcutajar]

I have a cheapo chinese lathe which I used for the last 5 to 6 years. Lately I have been hearing unusual clicking/arcing sounds when the motor starts. Today during a lathe session the motor would not start or start with slow RPM. When it does not start if I turn the chuck by hand it would start at a slow RPM. After about 7 seconds with slow RPM it gradually picks up normal RPM.

The motor has two large capacitors. Is problem with the capacitors? If so which one? Or is it one of the windings? Should I bin it and see what replacement I can find?

Any suggestions would be welcome

Happy new year.

 

[Herbiev]

It certainly sounds like a start capacitor problem to me

 

[vcutajar]

Thanks Herbiev for the reply.

This evening I investigated the motor capacitors. There is a label on the motor which states that it is a Single Phase Two Value Capacitor Induction Motor. I took the cover off the capacitors and the terminal block. One capacitor is 15uf 450VAC and the other is 75uf 250VAC. Everything looked ok except that one of the terminals of the 75uf capacitor was a bit blackened. This capacitor has a sort of rivet which holds the solder tag. I cleaned it up and started the lathe. The motor started normally but that blackened terminally was arcing. There was a loose contact between the rivet and the solder tag. I cleaned it up as best I could and soldered the rivet to the solder tag. Now the motor starts without any clicking/arcing sounds.

 

[John Rudd]

I suggest you change said cap before too long...its demise isnt that far away even for a temp fix..

 

[vcutajar]

Yes you are right. I will start shopping around for both capacitors. At least now I have their values.