Speed controlers

We’ve had a problem with speed controlers burning up. We’ve lost three or four already, and we are concerned about the competition. The speed controlers we’ve lost were not all from one motor, though it seemed that way at first. What exactly would cause a speed controler to burn up? We don’t want to lose anymore, especially with Murphy’s law.

Usually its from bits of metal shorting out the transistors inside. Or if you wire the input reverse.

As Patrick pointed out, about 90% of all Victor failures are due to metal shavings and dust falling into the device. All machining should be done only after the electronics have been covered. And a close inspection after is essential. Following that, you need to be sure that the device has in fact failed. What have you experienced? No output, smoke, drives in one direction but not the other? What is the LED on the Victor doing?
The remaining 10% of failures can be explained by loose PWM cables, improper crimps on the input and output (including the breaker panel and motor common returns), failure to connect the correct power polarity, blocking of the fans and driver abuse. As hardy as the Victor is, repeated and rapid, full throttle direction reversal will result in failure. The motor is a complex load and the rapid reversal of direction just makes this worse.

Are you using dual motors per gear box with Y-Cables?

If so, are the Victors set to BRAKE?

If so, then this might be caused by a bad Y-Cable connection.

Motor A is on BRAKE because it is getting no signal, while motor B is trying to move forward and they end up fighting each other, drawing lots of current and popping FETs.

Disconnect the motor leads and run the joystick around and make sure the Victor lights all agree before reconnecting the motors.