Lathe won’t start under load

[Gordon TarlingParticipant @gordontarling37126]

My Compact 8 lathe motor suddenly seems to be having a problem when starting – if the drive belt is actually driving the spindle, it doesn't start and just sits there and hums until I manually give the spindle a flick in the right direction. With drive belt(s) disconnected, the motor starts reliably in either direction every time. I'm fairly sure that the start centrifugal switch is working, as I can hear it click as the motor comes to a stop. The start capacitor looks OK, but if it's starting to fail, will this cause the lack of starting torque? I've got a new capacitor on order, but just wondering if anyone has any other thoughts.

[Gordon TarlingParticipant @gordontarling37126]

[Joseph Noci 1Participant @josephnoci1]

The start capacitor looks OK, but if it's starting to fail, will this cause the lack of starting torque?

Absolutely! Perfect symptom of a failing cap.

Joe

[EmgeeParticipant @emgee]

Gordon

Sometimes a failing capacitor will swell around the connection end so to be convex, in extreme cases there can be some leakage, as Joe says sounds like it has failed, you will soon know when the new one is fitted.

Emgee

[Gordon TarlingParticipant @gordontarling37126]

Thanks chaps, the new cap should arrive tomorrow, so I'll let you know if that fixes it.

Gordon

[Neil WyattModerator @neilwyatt]

I had a capacitor fail with no visible change.

Neil

[Gordon TarlingParticipant @gordontarling37126]

New cap arrived this morning, fitted and all working again! Thanks chaps!

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