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wutsurname 10-02-2009 03:41 PM

Motor Polarity
 
I just got 2 traxxas 550 titan motors to put on a clod more for bashing than strictly crawling. I was wondering if running the rear motor with reverse polarity would have any adverse effects on the motor? I can't find any numbers as to the timing on the motors but if they are advanced, wouldn't reversing the polarity act as running the motor with the timing retarded the equal amount?

EeePee 10-02-2009 03:50 PM

You are exactly right about the timing and running it backwards.

Bad for the motor.

They used to make reverse rotation motors because of that, first one I think of are the Kyosho Magnetic Mayhem motors.

So not the greatest choice.

clockworks 10-02-2009 05:40 PM

Standard silver can 540 motors, as supplied with Tamiya kits, etc, seem to run zero timing. It's common practice with 4-cell carpet racers here in the UK to swap the motor side to side every few race meetings to even out the brush/comm wear. They normally run slightly better in one direction, but this is due to manufacturing tolerances in the timing, rather than by design.

I've no idea whether all sealed can motors are like this, but it should be easy to tell if your 550 motors have near to zero timing.
Connect the motor directly to a 4-cell pack and listen to the noise it makes. Reverse the battery and listen again. If it sounds the same both ways (same RPM), it's zero timing.

wutsurname 10-05-2009 09:21 PM

Thanks for the help guys. I did some reading and apparently having the timing retarded will produce less power but also bring down the operating temps as well which was a problem I was having with my rear motor before. I haven't really read anything saying that reverse polarity is destructive though.

JohnRobHolmes 10-05-2009 09:24 PM

Reverse timing destroys the comm really fast. Reducing the timing does lower temps, until you hit negative timing.


Optimal timing is generally 7 degrees for forward rotation without excess wear or heat, so zero timing is even a compromise.

wutsurname 10-05-2009 09:29 PM

So is there any way of me changing the timing of my rear motor then? If I somehow turn just the outside can 180 degrees and run the reverse polarity would that make the timing advanced while maintaining the reverse rotation i need?

JohnRobHolmes 10-05-2009 09:37 PM

You will have to notch the can for reversed timing. Not really worth it for a titan motor unless you have lots of time and little money.

Manning 10-06-2009 05:20 AM

I haven't messed with the big motors, but on the "370" size motors there are two little holes in the endbell that snap ring pliers will fit into, and it's fairly easy to adjust the timing, by twisting the endbell. Makes a HUGE difference if the timing is correct for the intended rotation.

Nate08 10-07-2009 02:05 PM

If you've been running the rear motor reversed already it's probably well on it's way to shot so I wouldnt waste time or energy trying to reverse it.

Traxxas has reverse rotation motors out for the e-revo that will work great in the rear of a clod.

benoj 10-07-2009 02:29 PM

if i remember right when those titans are run in reverse they overheat much easier because the internal fan spins in the wrong direction to cool them

Nate08 10-07-2009 02:30 PM

Quote:

Originally Posted by benoj (Post 2033974)
if i remember right when those titans are run in reverse they overheat much easier because the internal fan spins in the wrong direction to cool them

Not the fan....regular rotation titans come out of the package with advanced timing.

wutsurname 10-08-2009 09:09 PM

Are those reverse rotation motors the same number of turns as the original titans or will i have to buy 2 new motors?


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