Burning motor controllers on flywheels

I just finished building a single flywheel with approximately an 18 to 1 gear ratio(a little under). After running the flywheel for a short while I managed to burn out 2 motor controllers. I am ramping the flywheel speed and the flywheel doesn’t have a lot of friction. What am I doing wrong? We have a competition on Saturday, so any help is greatly appreciated.

By the way, I am new member. How do you change the title?
EDIT: Never mind, I figured it out

Are you sure you burnt out two motor controllers or did you burn out the motors? Also, do you only have two motors on your entire flywheel assembly or are there more than that?

I have 4 motor, and I am sure I burnt out the motor controllers. There was smoke rising from the motor controller both times.

That is bad, probably something wrong with the brain :frowning:

That’s not good.

Is the overall gear ratio 1:18 or is it external 1:18 + speed or turbo internal gear?

Are the motor controllers old? Or it keeps burning out the controllers?

If it is an overall ratio of 1:18, by right it shouldnt be burning anything.
Unless there is still a lot of friction involved. But even then, the PTC should trip before anything start to smoke.

External 1:18 with internal for speed. When I get to my supplies tomorrow I will try to find brand new motor controllers.

Burning motor controllers shouldn’t have anything to do with your flywheel 's build or operation, it is most likely due to a short in the wiring somewhere. Check all of your wires that they are connected right and there are no frayed or damaged wires.

Could it be that one motor’s ptc trips and then it is forced by the other motors and that somehow hurts the motor controller?

You are probably right.

One of the motors was broken, and then fixed by soldering the broken wires together, while still being a legal VEX part. Could this have any effect?

I think it’s very unlikely that backdriving a motor could damage a motor controller, I have only ever heard of them going up in smoke due to a short. When you back drive a motor the power goes right through to the cortex, I remember last year if you pushed the lift down quickly when the robot was off the cortex leds would flicker for a moment.

I don’t know exactly how the repair job was done, but there is a good chance this may be your problem if it was done poorly. I would definitely use a new motor if this is the one your fried motor controllers were hooked up to.

That could be the reason.

Do check your wiring. Sometimes it could even be as innocent as zip tying the bundle of wires too tight and it cuts into the wires.

But it should be due to short circuit.

I, too, vote for a shorted wire. If it’s not at your solder repair, then look near where the motor wires enter the motor housing. That’s a very common failure point for shorted wires.

Swap out the motor with the solder. Given the motor wires were mended quickly due to wires getting snagged in gears in past project, there way be other points of failure as indicated by other posters causing shorts.

Use this as a cautionary tale as to why wire management is so important near moving parts.

Ok, I will do that.

Thanks everyone! Our flywheel is fully functioning now.