Can I safely reverse the polarity of this motor controller?

[omegagamer89]

Does anyone know if you can safely reverse the polarity on this type of motor controller? (red to black and black to red, instead of the current setup of red to red and black to black)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251147109564

Ok, so I got all my bugs worked out, and I hooked everything up and mounted the motor to the bike frame, only to discover that, when I turned it on, the motor spun the wrong way, and would basically have had my bike moving backwards.

Now, I CANT move or flip the motor around, due to the fact that
A) The gear on the motor has to stay on the right side of the bike, because the gear on the wheel is on the right side
and
B) flipping the motor around and then moving it farther to the right so that it spun the right way would cause the motor to stick out far too much.
Its hard to explain without seeing it, I think.

Anyway, the bottom line is, I CANT move or flip the motor, so I HAVE the make the motor spin the opposite direction. I thought maybe I could do this by reversing the polarity of the connection between the battery and the motor controller (linked to above) but Im pretty sure this would burn out my controller.

Does anyone know if this is the case?

Also, what about if I reversed the polarity of the connection between the motor controller and the motor? Would that work?

Any help is greatly appreciated.

 

[Samd]

Yes, I had the same experience with my brushed Aprilia - I reckon you can REVERSE THE OUTPUT WIRES. It looks like an LBD14 type or similar , so you *should* be ok.

Just don't sue me if it's my unlucky day. I doubt it - brushed motors are generally reversible for polarity (actually I think always).

Don't reverse the input wires, just the two output ones.

 

[omegagamer89]

So you mean reverse the ones from the controller to the motor, correct?

I just want to be sure before I try it. Im pretty sure I fried my first controller by reversing the polarity between the controller and battery, and I dont wanna fry my second one.

But reversing the polarity (red to black and black to red, instead of the current red to red and black to black) SHOULD be ok as far as you know?

 

[Samd]

Ebay ad says its a YiYun YK31c. See the pic.
http://res.bht-diffusion.com/velo/contolleur/BHT-YK31C-36V-500W.jpg

Keep the thick red/black pair going to pos/neg on the battery respectively, do not change these. These are the two bulk ones between the controller and battery. If it is a YK31c.

But you can reverse the thick yellow/blue OUTPUTpair. These should be the two between controller and motor. The motor will spin the opp direction....

 

[omegagamer89]

Ok! So I just went down and tried this with my spare motor and controller (Turns out I DIDNT burn the first controller, I just melted part of the contacts when the wires shorted together and spakred)
and it DID in fact spin the opposite direction. Everything seems like it should work fine.

There is only one thing I noticed. When I reversed the polarity from what it normally is, the motor seemed to have more... kick... to it, when it first started.
What I mean is, I dont have this mounted to anything since its just my spare, and so when it starts up it jumps just a bit. I have a brick laying over the wire to keep it from jumping TOO much.
What I noticed is, when I ran it with reversed polarity, it seemed to jump considerably more. It doesnt really cause a problem since it only jumps when it very first starts spinning, but I just thought it was odd that it seemed to have more "kick" to it with reserved polarity, even though it was the same voltage and wattage and such.

Does anyone know why it might do this?

 

[ddk]

it's caused by how the brushes have set-in on the motor. If the motor was only turned in the same direction for any length of time the brushes wear down and 'fit' with the commutator.
Reversing the motor causes the brushes to have to 'fit' the new direction.

 

[amberwolf]

It's also possible the motor has the brushes "advanced" (rotated in a particular direction) so that it runs differently in one direction than the other. It's common on certain kinds of motors that are only meant to be run in a single direction. Some have adjustable advance (or retard), by loosening screws on the brushholder and rotating it; many are fixed.

Powerchair motors like the ones I used on CrazyBike2 at first are advanced, and they ahve a bigger kick in the advanced direction, usually.

So probably yours are now in the "correct" direction if they are advanced, since they kick more this way.