7" Milwaukee Grinder Won't run?

brino said:
Yeah I think we all know that acrid smell. It always seems to stay in the air for days.
It does sound like a possible bad motor winding......DANG!

I once bought a big heavy grinder for cheap at a yard sale. No way to test the motor, but it was almost free.
Got it back into my shop and yup the motor was dead.
However the shaft was long enough to mount a pulley between the motor and the grinding wheel.
I ran it that way for years with another motor mounted behind it, and then changed to under-bench mount.
Do-able if the original motor bearings are still good and the grinder is good enough to warrant the work.

Brian
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Thanks again for all your help. This grinder while decently made is not capable of adding a pulley as it's a typical bench grinder nor is it worth any additional investment. It served me well for many years and it owes me nothing but I still feel defeated LOL.

Stay well,

Joe
 
You should feel victorious knowing that it is not going into a dumpster for a $5 fault.
A verdict of "beyond economic repair" is a smart decision.

Beside, it sounds like you learned a bunch from the investigation.
That is certainly a win!

Brian
 
It does sound like as you rotate the grinder, one of the motor windings is shorting. IF you desire to continue your quest, pull the motor out of the housing and look for areas of high soot, then examine the reason for the movement of the winding. It may be as simple as filling an area void with epoxy.

If you instead want to cut your losses and move on, we will certainly understand - you can only beat a dead horse for so long.
 
SLK001 said:
It does sound like as you rotate the grinder, one of the motor windings is shorting. IF you desire to continue your quest, pull the motor out of the housing and look for areas of high soot, then examine the reason for the movement of the winding. It may be as simple as filling an area void with epoxy.

If you instead want to cut your losses and move on, we will certainly understand - you can only beat a dead horse for so long.
Click to expand...
Thanks, I appreciate your insight, truly.

Joe
 
brino said:
You should feel victorious knowing that it is not going into a dumpster for a $5 fault.
A verdict of "beyond economic repair" is a smart decision.

Beside, it sounds like you learned a bunch from the investigation.
That is certainly a win!

Brian
Click to expand...
Thanks for your encouragement, sentiments and kind words, Brian.

Stay well,

Joe
 
As to un-sticking the relay... one might (carefully) wire the coil to AC (through a filament
light bulb, to limit current) and with the relay on a cushion, give it a few whacks
with a rawhide hammer... if the contacts are just lightly stuck, that could
free them.
 
whitmore said:
As to un-sticking the relay... one might (carefully) wire the coil to AC (through a filament
light bulb, to limit current) and with the relay on a cushion, give it a few whacks
with a rawhide hammer... if the contacts are just lightly stuck, that could
free them.
Click to expand...

It doesn't look like the relay was the problem after all.
 
Gents, sorry to beat a dead horse but this morning before admitting defeat and chucking the grinder into the trash, I tried one last test. I wired the grinder directly bypassing the motor relay and capacitor.

I switched it on and gently turned the shaft to get it to run and she fired right up. I let it run for 20 minutes and the motor barely got warm.

So, my completely uneducated guess is the motor windings are fine and the problem is the relay. The challenge is to find a suitable replacement hence me coming back here with hat in hand seeking guidance as to a source? Are there alternatives to the relay?

In any event, again, my sincerest thanks. Without the guidance from all of you, I would have known where to start.

Joe
 
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Hi Joe,

No apologies required.

It sounds like you have narrowed the issue to the motor start circuit (cap, relay start winding).

jbaccell said:
Are there alternatives to the relay?
Click to expand...
Actually the relay is alternative to a centrifugal switch than many earlier motors had.

Let me poke around here for a few minutes, I think someone (@Ulma Doctor , maybe) had posted about some solid-state alternative......maybe he (Mike) will see this reference and chime in.

Brian
 
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