Need help with troubleshooting AC ELectric Motor
 

Gentlemen (and Ladies) -

Helping out a friend. Craftsman 10" radial arm saw. Was told it
worked when put away. Now the motor hums when turned on. Giving it a
little push gets it turning slowly.

The 120V motor has a very slim profile. I found a capacitor external
to the motor. Replacing it made no difference. I also observe that
the wiring from the motor (3 leads, wht, blk, red) as well as the AC
from the on/off switch and the capacitor connect to a square gadget
with spade lugs. The L1 line apparently goes through a heavy wire
coil that bridges two of the terminals, to what I assume is the run
winding lead of the motor. (blk)


This gadget has a marking "3CR 118 931". I would like to know what it
is and also the likelihood of it being the problem. There isn't much
to it, I don't know if it is actually anything more than a terminal
block.

If it will help I can scribble up a wiring diagram or even attach a
photo of the device.

Regards - Tony

Need help with troubleshooting AC ELectric Motor
 

"Clive" wrote in message
...

Helping out a friend. Craftsman 10" radial arm saw. Was told it
worked when put away. Now the motor hums when turned on. Giving it a
little push gets it turning slowly.

Possibly a PSC motor with one burned out winding.

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Need help with troubleshooting AC ELectric Motor
 

Clive wrote:
Gentlemen (and Ladies) -

Helping out a friend. Craftsman 10" radial arm saw. Was told it
worked when put away. Now the motor hums when turned on. Giving it a
little push gets it turning slowly.

The 120V motor has a very slim profile. I found a capacitor external
to the motor. Replacing it made no difference. I also observe that
the wiring from the motor (3 leads, wht, blk, red) as well as the AC
from the on/off switch and the capacitor connect to a square gadget
with spade lugs. The L1 line apparently goes through a heavy wire
coil that bridges two of the terminals, to what I assume is the run
winding lead of the motor. (blk)


This gadget has a marking "3CR 118 931". I would like to know what it
is and also the likelihood of it being the problem. There isn't much
to it, I don't know if it is actually anything more than a terminal
block.

If it will help I can scribble up a wiring diagram or even attach a
photo of the device.

Regards - Tony


Have you looked into getting a manual from Craftsman? Most decent power
tools have replacement parts available and the manual will show what
everything is.

Need help with troubleshooting AC ELectric Motor
 

The "gadget" turned out to be a motor start relay. The start winding
was not getting switched in. Google up "3cr motor start relay" if you
are curious.

Thanks for taking the time to respond.

- Tony