flyer2222

Hi I bought a new Atomic force motor and when It starts to draw around 25 amps it sparks and turns the brushes black I tried retimeing it but it dident stop the problem, i have some old motor's that dont spark at 30 amp draws.
Any one know whats wrong?(maybe it's not ment to be fast?)

davidfee

My first impression is that the timing is not advanced enough. It could also be that the brushes are too hard, too small, or just not seated well enough. 25A really is about the max for a relatively cheap brush motor though. How many cells are you using? Is the motor loaded with a prop, or some other device?

-David

flyer2222

I’m using a 3.5 to 1 gearbox spinning a 12 by 8 prop and using 6 cells .the brushes a fairly big , bigger then most of my motors anyway.
Do you think theirs anything i could try to reduce the problem? (You said the brushes are to hard maybe I should loosen the springs?)
The pic is the top of my motor.

davidfee

Is that motor set up to run the right way? For the gearbox, I mean? From the pic, the motor is either at the fully retarded seting for normal, or fully advanced setting for reverse operation. But maybe the middle setting is not neutral timing, if you know what I mean. You could observe the no-load current as you adjust the timing.

As for the brushes, there are softer and harder ones you can buy... but I'm not familiar with that motor. I think softer ones are usually better for high-power, but they obviously wear faster.

Good luck,
-David

flyer2222

I have not done much with timeing so i dont know what will do what to revers it I just swiched the + and - around.
Is ther a forum on timeing ?

PHIL I.

IDEA.....

Put the prop on and notice which way the ARM turns. To ADVANCE the timing, you want to turn the brush plate opposite of the way the ARM turns. To retard, you turn the brush plate the same way as the arm turns.
A good way to come close to the optimal timing is to use 2 AAA batteries and free rev the motor and play with the timing till you get the best--highest--RPM in the right direction for the prop.

When I got my SKYSCOOTER, the motor was anemic and ran hot. It was timed for direct--push on--props. Not gear drive. I retimed it this way and it was a totaly different plane!

Also check to see that the brushes go through the brush hood easly.The sparking can be caused by the brushes hanging up and /or the springs are weak and the brushes are bouncing of the comm.
[8D][8D]
GOOD LUCK,
PHIL I.

flyer2222

Ther are almost no sparks but now the motor runs to hot! Any ideas?

davidfee

Did you change something? If so, what was it?

No sparks is good... running hot is not so good. It could be over-advanced (among other things). Are you measuring the current still?

-David