InstructorNotFound
New member
- Joined
- Apr 17, 2023
- Messages
- 1
Preface: My circuits knowledge is limited. Also having trouble uploading photos (probably because first post?) ((Edit: maybe I was able to attach them but not insert them)), so I'll try to be descriptive.
Chicago Power Tools Model 9875 3/4hp 3450 rpm 60 Hz 110v 6amp --- can also be wired for 220
Got this old bench grinder that was working but looked its age and made a racket, so I took it apart and painted it. When I reassembled it, I thought I put everything together and rewired it correctly, but it wouldn't run - only hum. Eventually I tried spinning the shaft and that would get it going and I would hear the click of the spring mechanism on the shaft switching it to direct power. This made me think that perhaps there was originally a capacitor but then the previous owners removed it after it blew and just bypassed it. I figured it maybe worked before but perhaps there was more friction when I reassembled it. The shaft doesn't spin super freely and stops shortly after I try to manually spin it. I didn't try to put new bearings in it because I thought they'd be good enough.
I tried buying a start capacitor rated for 110-125 VAC and 108-130 MFD, but when I wired it up, it still wouldn't start though it did seem like I needed to add less manual force to get it going. When I got it, the red wire from the power cord and the red and grey wires going to the motor/spring mechanism were all together in a twist cap. I tried the red power cord wire and grey wire on 1/4 quick connects on one of the capacitor terminals with the red motor/spring mechanism wire on the other terminal. This didn't work and then I tried the grey w the red power cord. After trying a few times, I had it on for a few seconds hoping it would go, and it eventually blew.
Do I need a bigger capacitor (pretty lost on how to size them as most calculators seem to be based on Joules and I don't know the force I need to get it started spinning)?
Do I need to wire it differently?
Do I need new bearings?
Or what else am I doing wrong?
Thank you
Chicago Power Tools Model 9875 3/4hp 3450 rpm 60 Hz 110v 6amp --- can also be wired for 220
Got this old bench grinder that was working but looked its age and made a racket, so I took it apart and painted it. When I reassembled it, I thought I put everything together and rewired it correctly, but it wouldn't run - only hum. Eventually I tried spinning the shaft and that would get it going and I would hear the click of the spring mechanism on the shaft switching it to direct power. This made me think that perhaps there was originally a capacitor but then the previous owners removed it after it blew and just bypassed it. I figured it maybe worked before but perhaps there was more friction when I reassembled it. The shaft doesn't spin super freely and stops shortly after I try to manually spin it. I didn't try to put new bearings in it because I thought they'd be good enough.
I tried buying a start capacitor rated for 110-125 VAC and 108-130 MFD, but when I wired it up, it still wouldn't start though it did seem like I needed to add less manual force to get it going. When I got it, the red wire from the power cord and the red and grey wires going to the motor/spring mechanism were all together in a twist cap. I tried the red power cord wire and grey wire on 1/4 quick connects on one of the capacitor terminals with the red motor/spring mechanism wire on the other terminal. This didn't work and then I tried the grey w the red power cord. After trying a few times, I had it on for a few seconds hoping it would go, and it eventually blew.
Do I need a bigger capacitor (pretty lost on how to size them as most calculators seem to be based on Joules and I don't know the force I need to get it started spinning)?
Do I need to wire it differently?
Do I need new bearings?
Or what else am I doing wrong?
Thank you