How To Motor wiring/ overheats, help with coils

[Greenberg Woods]

Hey Guys, i have this bug Disc sander i bought a while ago. It seems to be shop built, but after running in for no more than ~20 minutes at a time the heater coil flips and the machine turns off. Im not great with this sort of thing, but It looks like it should be correct, so im not sure what the error is.

As far as I can tell, The coils are #1037, set in the high position. Which gives its min-max as 11.4-11.9. The motors Service factor is 1.15, and at 115 volts its 20 amps.

If the numbers in the table are amp rating, none of the coils go up to 20 amps. Would that mean i would need to convert it 240 volt to run it at 10 amps? Or get a higher rated coil?

Not sure when to do, as the amp rating of the motor is higher than the highest coil recommendation. Thanks for your help guys.

 

[Ken H>]

A bit more info please. Have you been running this very much in the past? OR, just now starting to run?

Does it have the remote START-STOP pushbuttons?

Are you running it on 120 vac now? You've wired the motor for 120 VAC?

It sounds like you have OverLoad coils for 220 vac at 10 amp load. When running on 120 VAC you're looking at 20 amp max which would put more load on the OverLoad coils causing them to trip after a few minutes running, just as you're having. Would it be possible to use 220 vac?

 

[Mahoney]

Yes, if you convert the motor to run on 240V the heater coils are about the right size. The motor starter relay may still need to run on 120V. That should not be a problem but you will need a 4-wire 240/120 outlet to plug it into. Or you could replace the motor starter. Made in USA ones tend to be almost expensive as a new machine. I've bought imported motor starters from Woodworker's Supply of New Mexico and Grizzly that have held up OK.