Protecting a Repulsion Induction Motor

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Forum topic by Cwolfe posted 05-11-2010 07:53 PM 2964 views 0 times favorited 5 replies Add to Favorites Watch
View Cwolfe's profile


7 posts in 3041 days

05-11-2010 07:53 PM

I recently bought a Unisaw that has a Repulsion Induction Motor and heard how expensive it is to replace/repair. I was wondering what is the best way to protect this motor from burning out, I would really hate this motor to break down. I was thinking of some kind of switch with a overload element but im not really sure whats the best way to get it/ set it up.
Any help that would help prevent the motor from dying in the future would be greatly appreciated!

5 replies so far

View TheDane's profile


5448 posts in 3692 days

#1 posted 05-11-2010 09:59 PM

Other than to perform routine maintenance and cleaning, I’m not sure there is really much you can do to protect these old motors.

If you have a motor repair shop in your area, check with them to see if there is anything you can retro-fit to it.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View SCOTSMAN's profile


5849 posts in 3614 days

#2 posted 05-11-2010 10:07 PM

If it breaks down and is irreplacable owing to costs then you will have no choice but to buy a different type.In the meantime I hope you have many years of fun together.Alistair

-- excuse my typing as I have a form of parkinsons disease

View dryhter's profile


74 posts in 3633 days

#3 posted 05-12-2010 12:10 AM

Go here

-- Chips and Shavings/ see you at

View uffitze's profile


199 posts in 2984 days

#4 posted 05-12-2010 12:35 AM

as far as the NEC is concerned, you don’t need additional overload protection if your saw isn’t “permanently installed”. (Ie. if it is plugged in.) the branch circuit overcurrent protection device takes care of providing the overload protection.

that said, if you want ‘em, you should be able to pick up motor overload protection at your local electrical supplier. the size you need depends on how big the motor is, and for overload protection it’s based on your motor’s full load amp draw and service factor/temp rise. FLAx1.4 for motors with a service factor of 1.15 or greator or a temp rise of 40 degrees C or less; FLAx1.3 for all other motors.

View TopamaxSurvivor's profile


18293 posts in 3705 days

#5 posted 05-12-2010 02:31 AM

My guess would be that it is already thermally protected. Do you have a motor starter type relay that comes on to start the motor or does the nameplate say it is thermally protected? It may have a reset button or it could be automatic reset.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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