Won't power on, new ac contactor

yeah the manual was certainly lacking on troubleshooting advice. but its resolved now and on to other issues. my lathe motor has now stopped running in forward, it just kinda buzzes … reverse seems to work.
 
It sounds like the start winding isn’t in the forward circuit for some reason. Did this just start after replacing the contractor?


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it worked for several hours after replacing the contactor then just stopped working. it was cutting fine, stopped to measure and it wouldn't start again in forward, but it would run in reverse. I am hoping its the 50Uf run capacitor.
 
It could be an unexpected cap failure, on the other hand it's a good rule of thumb to suspect the last thing you did. In this case, are you sure the replacement contactor is functionally the same as the old one and is wired up exactly the same? Problems with only one direction would tend to indicate a problem with the reversing switch...or wiring thereto
 
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I think the contactor is working properly since the machine worked for several hours after changing, but how would I test it, or test the switch?
 
Does it work in both forward and reverse when you manually engage the contactor? If not then it may be a problem with the reversing switch
You would need to remove the switch and test it for continuity on the bench- does this machine have a lot of hours on it?
Check the wiring to the switch first in case there is something loose or freaky- shut power off
I'll take another look at the Grizzly diagram, see if there's anything else it might be
 
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This machine has two motors correct? And two reversing switches?
 
If you select forward, and the contactor pulls in, then it is either a motor fault, or the feed to the switch side of the contactor is not there. If the contactor does not pull in, suspect the safety circuit again. If the motor is buzzing, does sound like start capacitor fault.
 
Because it's working in reverse, I suspect the reversing switch. The way it operates is, it's reversing the start windings. Because it's buzzing in forward, I believe the starts aren't in the circuit.
 
According to the Grizzly diagram the contactor just supplies mains power to both motors, each with it's own reversing switch.. it has to be the switch
these chi-com switches are not real reliable
 
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