[How-To] Help with grinder

markba633csi said:
It would be wired in series with either the wire from the centrifugal switch or the one from the start winding (both look like light colored fabric covered wires in post #1)
Polarity doesn't matter
So, one of those two wires goes to one post of the cap, the other post of the cap goes to power. If in fact this is a capacitor start motor.
-M
You mentioned in post #1 that the motor was working, if so why did you assume a cap was required/missing? Was the motor starting sluggishly?
Looking at post #5, it looks to me (if that's the factory wiring, and it may not be) it would be a tight squeeze to stuff a cap in there
Click to expand...

To be honest I just assumed. I could 100% be wrong. I was thinking since it had that cap it was missing it. Other Sanford surface grinder motors of the same size do have one. I thought a motor would still run without it but it could potentially cause issues? Sorry if this all is annoying I’m sure you can tell I am guessing. Thank you for the information and diagram. Do you think it would be better off without it? I am willing to just leave it how it was and see what happens.

I made another post when I first got the grinder and the mag chuck wiring was mangled. It looked like someone hacked it together. With that I think I just got dead set that who ever did the wild paint job and mag chuck wiring did something to
The motor too.

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You could wire in the cap and try it out, it may start a bit faster. I don't think you can damage anything.
Troubleshooting sometimes takes a bit of back and forth, personally I don't mind spending the time if I can help someone out
-Mark
 
markba633csi said:
You could wire in the cap and try it out, it may start a bit faster. I don't think you can damage anything.
Troubleshooting sometimes takes a bit of back and forth, personally I don't mind spending the time if I can help someone out
-Mark
Click to expand...

Again thank you, I will post back once it is up and running again.


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if the motor ran without added capacitance, you don't need to add a start capacitor
you may damage windings if you select a value too high
 
For a run cap, possibly, but for a start cap I think the chances of damage are pretty low. The start winding is powered for only a moment
 
OK now I think we are getting somewhere. The bridge rectifier was miswired and might be damaged now.
The negative terminal is on the diagonally opposite corner from the plus. The AC terminals often have a sideways "S" which is a symbol for a sine wave.
Secondly, your chuck coil may be bad or your meter is giving odd readings. Does the meter zero when you short the test leads? Try measuring the 35 ohm resistor on the 200 ohm and 2000 ohm scales to check it.
We can also test your bridge if the meter is ok, but if the chuck coil is bad you have bigger fish to fry
-M
Click to expand...
Unfortunately the meter works fine, on 200 and 2000 it reads the 35 ohm resistor perfectly. I am at a loss, when I bought this grinder I did test it, the mag chuck and the motor worked. Then somehow in travel it stopped working when I got home and tested it the mag chuck no longer held. I did a post about it and showed the wiring, it was all pretty bad.
 
I just tried wiring it like this. The resistor did not get hot and the mag chuck kinda worked. I was able to pull off the piece with some force, so I think it should be stronger. I did not wire in the motor.
947f0af5aa1c751d13828590a2d66fc1.jpg



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OK well it may be that the chuck is partially open circuit but it sounds like it's working, or trying to.
Did you observe the polarity of the cap? Some caps have one lead marked with a plus and some with a minus. Make sure it's correct, or the cap may explode or leak.
You could try eliminating the 35 ohm resistor- that would be the chuck's maximum force- it won't get any better.
-M
 
markba633csi said:
OK well it may be that the chuck is partially open circuit but it sounds like it's working, or trying to.
Did you observe the polarity of the cap? Some caps have one lead marked with a plus and some with a minus. Make sure it's correct, or the cap may explode or leak.
You could try eliminating the 35 ohm resistor- that would be the chuck's maximum force- it won't get any better.
Click to expand...
Ok, does that circuit look better than the first one? I was going to feed the motor switch straight from the + and - and not from the switch, since the resistor is feeding the power to the first switch. I think I wired in the cap right, it had a gray line down the side with an - in it, so I thought that was the negative side.

p.s.- So I am trying to understand how the mag chuck works. Is it the same concept as a coil tattoo machine, but with more coils? Also, if I use the continuity tester on my multimeter, it does not read from wire to wire. Is it possible to go in and repair the mag chuck if it is broke?
 
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