# Extra brushes for DC regen



## Guest (Dec 20, 2008)

DC motors for regen will have interpoles. Not more brushes. DC Series with interpoles will work but don't advance to high. 120 to 140 volts should be fine with a good large DC motor with regen. These are not SepEx motor. SepEx for regen will also have interpoles. I have both. 

My 9" GE is only a series motor without interpoles and can't be safely used for regen. That is what is currently installed in my Ghia. My Kostov patiently awaits installation. Looking for a decent controller that will do regen. Kelly is the only one available. I will look into this later. Or zapi H2. Anyone have one of those available?

Pete : )



booksix said:


> So we know that regen is difficult with a brushed DC motor because of the brushes being advanced for high voltage. My question: would it be possible to have a second set of brushes with retarded timing rather than advanced, which would be used solely for regen? Hope this isn't too dumb, but with my limited knowledge it seemed like it could work great.


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## Kirk_Wallace (Nov 20, 2008)

One thing that might be a problem is that brushes usually short two bars, so some of the coils will be deactivated. The brush carriers take up a fair amount of space, getting two sets of brushes, especially at the timing positions needed would be problematic. My guess is that a movable brush carrier that allowed for variable timing in both directions would allow for regen. Something like...:
http://hitorqueelectric.com/gallery/v/custom_motors/steel+brick/DSCN1872.jpg.html


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## booksix (Aug 26, 2008)

I was thnking that as well, but I think jim himself said somewhere that constant timing changes, even with his variable setup, wouldn't be very good. I was just curious if there'd be a way to have both and switch between them. I'll probably understand more once I get my motors and open them up.


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## Bowser330 (Jun 15, 2008)

This may sound wierd so dont flame me but...

what if you connected (siamese or belt/chain) two DC motors, one spinning one way (power user) the other spinning the other way (generator)...

While accelerating the generator is freewheeling and causing little drag to the other motor...as soon as the regen is activated (however you set it up), the accelerating motor will already be freewheeling/spinning, and the other DC motor will be energized and start to harvest all that mechanical energy..

Just a long shot.....

thoughts?


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## Kirk_Wallace (Nov 20, 2008)

In my internet searches for EV information, I have seen a couple of examples where an alternator was added to the traction motor shaft in order to do regen. The biggest problem seems to be that the power surge from braking is much higher and shorter than the output surge for acceleration. I tend to agree with one of the members here that commented that you would be better off adding more batteries for the same weight of a regen system needed to get a decent gain from braking, at least for a DIY system. Being able to very efficiently store these braking surges is going to need to be solved before regen becomes practical.
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Kirk
http://www.wallacecompany.com/machine_shop/


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## Bowser330 (Jun 15, 2008)

Kirk_Wallace said:


> In my internet searches for EV information, I have seen a couple of examples where an alternator was added to the traction motor shaft in order to do regen. The biggest problem seems to be that the power surge from braking is much higher and shorter than the output surge for acceleration. I tend to agree with one of the members here that commented that you would be better off adding more batteries for the same weight of a regen system needed to get a decent gain from braking, at least for a DIY system. Being able to very efficiently store these braking surges is going to need to be solved before regen becomes practical.


I see your point, however I am not sure about the whole battery weight vs regen system weight...we all know how heavy the LA batteries are...if you are talking about lithium-ion, ok different story, but LA batteries are heavy...


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