jackv202

Hi,
Can you help me? when i press the throttle on my rc car the motor does not turn, though if i hold down the throttle and turn the spur gear it starts up. but if i stop the motor then it wont start again until i have turned the spur gear to starte it up, what can i do to make it work properly?

I have tried a different motor and that is fine, so it is definately a motor problem. It had just had the comm skimmed and the brushes and springs changed. I have tried a different endbell, armature, springs and brushes but to no avail, it still doesn't work, please help me

Thank you

Jack Varty

sosidge

It sounds like a classic sticky brush.

I was going to say "check that the brushes move smoothly in the brush hoods" - but you say you've changed everything except the can.

This doesn't make sense - fresh brushes, cut comm and brushes that move freely in their slots should stop a sticky brush.

Try again, or use that other motor you've stripped parts off.

fatdoggy

Did you round the com slot edges with a ball point pen? Generally after a cutting the comm there is excess filings in the comm slots and you have to clean then out and then round the edges slightly. I'd say tear it down and check everything. Also if you didn't give it time to run-in at a low voltage you can have problems with sticking. That has only been a problem for me though when the motor is at full throttle. Another possibility is a loose magnet, make sure there ok and arn't moving around.

racer

check your gear mesh, also check to see if the screws you used to mount the motor are not touching the moving parts inside

Barry White

FAST, CALL 911!!!

calvin

Get a multimeter and check for continuity between the three comm segments. You should have continuity between all the comm segments. It is possible that the tang clamping on one of the wires is not making good contact. This will cause the problem you're having. Carefully clamping down on the defective tang with a set of pliers will usually solve the problem.

Tek Nickal

Sounds like the hung brush problem but the brush moves freely inside the hood. Weird.

edseb

Outside chance, but also check to see if the transmission is too bound, so once you get it going it continues with momentum. If running belts, check the wheels, etc. Also, check the brush shunts and make sure they aren't hung up on something. Check for pebbles in the gears too. Could be a few other things too.

Tek Nickal

He said he tried another motor and it worked fine. So yea.

fatdoggy

It may need more then a skim to make it perfectly round if it's been run more then a few times.

Still Bill

iTrader: (16)

Jack,

This can happen with one dead pole on the armature.

If having the "comm skimmed" means it was cut down on a lathe, did one of the pole wires get severed on the other end of the armature from the commutator? Have seen it happen when that end of the armature hits the lathe's support block while being cutdown on an improperly setup lathe?

JusBox

iTrader: (1)

just buy a new motor if you really need to. Might be easier than trouble shooting this one if you dont' have the time.

MrEs

go to the shop and buya new motor
then come back to fixing this one, then you'll have two mototrs because ur eventually going to use this one up and throw it for a new one anyway.

Greg Anthony

iTrader: (4)

Make sure you don't have a loose magnet and it is rubbing on the arm.

mb racer

iTrader: (1)

try using another arm from another motor just to see if it works ,, if it does , buy another arm ,, i cant say how the motor will run but at least youll have a good practice motor....good luck..