# Bad DC Motor?



## OrangeAlpine (May 7, 2013)

I have a 1hp treadmill motor that came with its OEM controller.  The speed control would work properly for a few seconds, then become erratic.  So I purchased a Graham Transmissions 1000 controller, rated up to 1 hp.  Hooked it to the motor, it started at top speed.   Cranked the speed down to zero, then started to increase speed.  The motor suddenly stopped - blown fuse.  The board now blows fuses whenever energized, even with no other wires attached.

I'm wondering, could the motor be killing the controllers?

Bill


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## itsme_Bernie (May 7, 2013)

I am more new than you on the DC front.  I wish I could help you.

So, to the best of your knowledge, this motor was working before you hooked it up?  


Bernie


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## OrangeAlpine (May 7, 2013)

The treadmill was junked because the speed control was funky.  The thing would run, but speed was all over the place, same as when I hooked it up.  It will regulate, but on an all or nothing basis.  No good for a treadmill or a machine tool!

I Ohmed the motor, 1.6 Ohms across the leads, infinite from leads to case.

Bill

- - - Updated - - -

It would run, but speed regulation was like a full blast of DC, then nothing until speed dropped.  It seemd to be running correctly when the new speed controller died, but it ran for a very few seconds.  

Bill


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## Chucketn (May 7, 2013)

I would carefully pull the end bell off the motor and check the brushes and comutator. Check for carbon dust from the brushes building up and shorting out segments.
What model controller came with the tmotor? I have several treadmill motors I have salvaged. I've tested them all and am using the two biggest on my mill and a wire wheel arbor. I may still have a 1 1/2 hp unused. Could trade for something...
Chuck


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## OrangeAlpine (May 7, 2013)

chucketn said:


> I would carefully pull the end bell off the motor and check the brushes and comutator. Check for carbon dust from the brushes building up and shorting out segments.
> What model controller came with the tmotor? I have several treadmill motors I have salvaged. I've tested them all and am using the two biggest on my mill and a wire wheel arbor. I may still have a 1 1/2 hp unused. Could trade for something...
> Chuck



Everything looks good, very little carbon dust.  The original controller has 30687 PWM printed on the circuit board.  The sticker on the outside says "Weslo, INC. P/N 031016".

What is the rpm of your motors?  I really like this motor, it rated max is 2400 rpm, which makes it a good match to my lathe.  

Bill


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## Chucketn (May 7, 2013)

Can't remember rpm specs off the top of my head, but I'll dig them out in the morning and get a pic and a list.
I was hoping the controller was the venerable MC-60 as I am quite familiar with them.

Chuck


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## OrangeAlpine (May 9, 2013)

I found the problem:  Energized the armature through the field circuitry!  At least I know the motor is good.

Bill


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