# Too much power!!!!



## avidsensei (Apr 25, 2016)

Well I roasted my brushes out of my ME0709!

Do you guys think a new set of brushes and a sanding of the armature will fix it or is it too far gone?


https://imgur.com/gallery/xwVvT7g


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## jonescg (Nov 3, 2010)

avidsensei said:


> Well I roasted my brushes out of my ME0709!
> 
> Do you guys think a new set of brushes and a sanding of the armature will fix it or is it too far gone?
> 
> ...


It's dead Jim


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## Duncan (Dec 8, 2008)

avidsensei said:


> Well I roasted my brushes out of my ME0709!
> 
> Do you guys think a new set of brushes and a sanding of the armature will fix it or is it too far gone?
> 
> ...


Looks like the main windings are OK - clean up the comm, get new brushes and have a good look at brush holders - they may need to be replaced

BUT FIRST!
Stick your multimeter on the field coils and armature - make sure that you don't have a "leak"
I blew my first motor up and was thinking about brushes until I put a meter on the comm segments to the armature core - expecting 20 megohms - oops 2 ohms!

Same with the field coils it turns out little globules of molten copper are really good at breaching insulation


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## major (Apr 4, 2008)

Hey Dunc, 

It is a PM motor, no field coils.

Looking back on the OP's post history I see where I answered a couple of questions about the motor and inquired of his application. Electric MC conversion. I am unsure why I didn't continue with it. Too late now.

I typically warn newbies against using brushed PM motors, for the very reason you see here. Most often they ignore me due to a number of reasons, mainly size and mass compared to a wound field motor, or cost compared to a brushless system.

Anyway, I suspect the cost of repair will exceed replacement cost. A simple replacement without changing other things in the system will probably be a repeat performance of his flameout. With changes needed to make the PM motor survive, he will be displeased with bike performance (acceleration, speed, hill climbing).

So a word of caution.

Regards,

major


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## avidsensei (Apr 25, 2016)

Haha, yeah, Major. I took the current limiter off by accident when I was changing things around on the controller. Wasn't thinking about it when I took it for a ride and I did 3 hard pulls to see how fast I could get it going and how the acceleration was. 
Turns out it has really good acceleration at 400A!!! But only for a bit.

The motor has been working really well for me, I have had it for 4 years now I think. Might be a bit undersized but I just use it for pleasure riding and back and forth to work.

New brushes, holders, and basically the whole back end of the motor is only $100.


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