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Does anyone know elec. motors.
I got a old belt sander to use it for parts to fix up one just like it I already had. This thing also had a motor on it. Dayton 120/240 1ph. 1 hp. First time I plugged it in, it groaned, spun shot tons of dust out of it, then tripped the breaker. Tried it again same thing happened. I tore it all apart cleaned everything didn't see anything obvious. I checked for shorts. Both the armature and the stator seem to be shorted out. I know this isn't right. I put it back together anyway, swapped a capacitor from another motor. Turned it on. It spun real good for about 5 seconds, then tripped. Is this motor trash. If I take it to a motor shop it would cost more than a new motor.
Thanks. Chris
 

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Bilge Rat
motors and controls.........
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Several possibilities here.

1) The insulation of the winding has broken down, allowing adjacent wires in the coils to short. The only cure is a re-wind. Costs about the same as a new motor.

2) The start switch in not disengaging. If the start winding is left energized, it will draw excessive current. Usually 3-4 times the running current. A simple test; wire a switch in series with the start capacitor. With the switch on, start the motor. After a second or two, turn the switch off. This will de-energize the start winding.

3) Is it connected correctly? Operated at the correct voltage?

NEMA established standard frame sizes in 1952, (the U frames) and updated them in 1964, (the T frames). The T frames are still standard today. If this motor was built in 1941, it's not a standard frame size at all.

If it mounts on something that can be drilled, a 56 frame can be made to work. The old motor likely had a 3/4" shaft, a 56 frame is 5/8".

One thing to try is a Grainger #4K047. It's listed as limited supply, they might be out of them completely, but if they have one it's less than $100. Another place is ebay. Go to 'business and industrial', then under 'industrial electrical and test', click on 'motors and transmissions'. There are lots of 1HP 1PH motors there for less than $100.


On a belt sander like this, I'd use a TEFC (totally enclosed fan cooled) motor. They're a little more money, but an ODP (open drip proof) will draw dust into itself, and it won't last long.

There are alot of cheap motors out there, usually identified by a nameplate RPM of 1720. Not well made. Might hold up ok for occasional use. If it's built to NEMA standards, it'll be 1725 RPM.

Rob
 

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What about using the motor from the other sander to check the operating condition of your new find.
As long as the bearings are in good shape, that thing looks like it’s well worth the expense of a new motor. A lot of wood workers would kill to have that sander since almost all of the new stuff from Delta and Jet, etc., is crap from China that doesn’t hold up to heavy use.
I would maybe check McMaster-Carr Supply to see if their prices are any better for a new motor.
 

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When you got it was there a plug on the cord or did you put it on?
 
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