Motor Capacitor Replacement ?s

Splat

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Guys, I need some help here please. My G4003G lathe's motor started slowing down while taking a really light cut the other day. Yesterday I go to start the motor at the 1400rpm setting and it wouldn't spin up unless I helped it. I spins up fine on slower settings tho. I'm thinking it could be either both start and run caps going bad or the motor itself. The motor seems to run and sound fine so I'm hoping it's the caps. The start cap is the one I'm unsure which to go with. The start cap is 150uF, 250V. McMaster has two ranged caps that might work, this 130-156uF cap, and this 145-174uF cap. I don't know which is the better bet to go with. Thanks.
 
Sounds like just a bad run cap- very slim chance both run and start caps are bad at the same time unless one of them was on the way out and the other one just caught up with it...
Mark
ps just checked the G4003 manual and the run cap is a 20 uF 450 volt unit.
As to your question about cap sizes, I would pick the larger one of the two. Make sure the voltage rating is equal to the original or larger.
 
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Thanks Mark. I'll try the run cap then first and see what happens.
 
Thanks Mike. I ordered one from McMaster. Yet another thing to work on this weekend.
 
I would replace both as they both deteriorate over time, as others have said check the size as they are often not a uniform size. I believe the ones from McMaster may be too large for the G4003G motor. You can also check pool repair shops, often the pump capacitors may be smaller. I had another machinist bring over his G4003G motor that stopped running, pulled the start capacitor and tested it DOA. The electrolytic capacitors go with time, the start is most common from overheating with frequent start/stops. Usually the lower uF higher voltage are film or oil caps. I have replaced my share in various motors capacitors out here in the hot desert, nothing seems to last with the heat.

On the G4003G motor capacitors on the one I saw the wires went directly into the motor, so you will need to cut the wires and use wire nuts or some form of insulated connectors. A number of people have also replaced the motor.
G4003G motor caps.jpg
 
Well, I could make another set of covers for them. I just looked up the caps part #'s on Grizzly's site and the one's from McMaster are a little bigger so I may have to make covers for the new ones. We shall see.
 
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