Milwaukee 6117 Corded Grinder Electrical Problem

[germanwrenchguy]

So I picked up this corded Milwaukee grinder with a broken bearing which I replaced.
After putting it back together, it won't spin.
It's making a humming noise and starts to smoke lightly when left on for more than a few seconds.
I can't spot anything that's obviously wrong.

Both Field Coils measure about 3 Ohms, no short, armature is not shorted either.
And it did spin before I disassembled it. I must be missing something.

 

[PCustoms]

Does it spin by hand while not plugged in/powered on?

 

[germanwrenchguy]

Does it spin by hand while not plugged in/powered on?

yes it does. Cant spin it by hand when it hums though. I replaced the bearings, it spins as freely as it should

 

[PCustoms]

yes it does. Cant spin it by hand when it hums though. I replaced the bearings, it spins as freely as it should

Did you remove any wires during the rebuild?

Did it spin up under power with the bad bearings? Previous owner may have burned the motor up if it was seized....

 

[germanwrenchguy]

Did you remove any wires during the rebuild?

Did it spin up under power with the bad bearings? Previous owner may have burned the motor up if it was seized....

I did remove the brush wires and the power cord.
Only thing I have put on incorrectly would be the power chord, but I already tried switching it around.
Since its A/C I wouldn't know the difference it would make anyways.

 

[germanwrenchguy]

Can I just remove the PCB and try to wire it directly to power? Or does the PCB more than just regulating speed?

 

[PCustoms]

I did remove the brush wires and the power cord.
Only thing I have put on incorrectly would be the power chord, but I already tried switching it around.
Since its A/C I wouldn't know the difference it would make anyways.

What did it do before you change the bearing? It was probably toast and you just put new bearings in a dead grinder...

Can I just remove the PCB and try to wire it directly to power? Or does the PCB more than just regulating speed?

I certainly wouldn't, not sure what the PCB does

 

[germanwrenchguy]

What did it do before you change the bearing? It was probably toast and you just put new bearings in a dead grinder...



I certainly wouldn't, not sure what the PCB does

it ran, sounded like low power and made a hell of a noise from that one bearing.
now its just spins way nicer on hand, but won't start spinning on power.

 

[PCustoms]

it ran, sounded like low power and made a hell of a noise from that one bearing.
now its just spins way nicer on hand, but won't start spinning on power.

If your confident in your mechanical assembly I would find a wiring diagram and verify it's correct.

 

[tarbellb]

very likely it was torched before

Don't worry, Milwaukee corded grinders **** *** even new

 

[American Locomotive]

I've seen this happen on brushed power tools before. Something is assembled incorrectly. When you turn the tool on, it the rotor gets yanked into the stator laminations and can no longer spin.