Frustrated newbie has motor issues

[yellafishdog]

Ok have to ask this question and hope that somebody can help. Why do I keep frying my motors? I have fried 2 motors in my b3 in the last two days and am reluctant to put another one in until I figure what I keep doing wrong. The second motot was new out of the package and last only two batteries. Both motors are 27 turns well within the limitations of the ESC. Both times the buggy just starts to lose speed and then stops all together. There is still plenty of power in the batteries to power the steering servo and when I tried to motor on another cars ESC it doesn't work, so I am sure it is a problem with the motor. Any help is GREATLY appreciated. Thanks, Jeff

[murphy3688]

If you've burned up two motors in two days, it's probably not the actual motors. Try putting a new esc in there and see how it goes; it has to be how the power is managed in your b3, and since one word in "esc" is "control," I'd start there.

Someone else might actually know, but that's just my thought.

[JakeE]

What gearing are you using?

[Vato Loco]

Are you leting the motors cool between battery packs? Stock motor run real hot and depending on your gearing and the type of surface your running on you really need to let the motor cool all the way down before running a nother pack through it! also Oiling the bushings before every run helps to keep things cool to.

[yellafishdog]

Thanks for the help. I just discovered that the second motor isn't actually burned up. After letting it sit for a while and re-soldering the motor connections, it ran great for one battery. Then after letting it sit for a while, the motor wouldn't run again. It seems that the motor is overheating. Does that sound right? If so, what whould be causing that after only one run? I have been running the same gearing on the same surface for a while without any other problems. Thanks for input

[ygguB naM]

What's the pinion and spur gear and is there a lot of drag in the tranny?

[Rick Hohwart]

The motor will not stop because it is hot. The ESC may shut off it it becomes too hot and prevent the motor from working.

Also make sure the motor brushes move freely in their hoods. If they are tight, or the shunt wire hangs up on the edge of the hood, the brush will lose contact as it wears and the motor will not work.

Also, a battery that is so dead that your motor won't work will still power your radio and servos. Make sure your battery is charging completely.

[highroller]

Depending on how times motors have been run the brushes may have worn down to the point the springs aren't able to provide proper tension. That's can one of the problems you decribe - motor runs fine for 1-2 minutes but begin to fade then stop. Compare the length of the brushes with a new set, if length is 1/4 shorter than original try replacing the brushes. Other causes have already been mentioned - overgearing, battery pack not fully charge, possible esc problems. Also look at the color of the wire around each armature stack - if wire has discolored (bluish-black) it's an indication that motors were either overgeared or under strain. Heat will cause brushes, comm, windings to discolor from a shiney copper to a bluish black - in extreme cases brushes may even turn a silvery color.