[Al Skierkiewicz]

Phil,
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.