An older robot of mine from 2004, Green Wave, which has a very powerful 15 HP Etek motor, in a 120lb combat robot. This was a match at Motorama held by Northeast Robot Conflict, NERC.
In this match, there was internal motor damage from the shock of a previous match. Upon testing the motor before the match, the internal short circuit caused enough current to weld shut the conatactor relay which controls the motor. After a moment, the internal short melted, and the weapon spun up freely, but stuck on.
My opponent, Death Drum, was a bran new robot, and he decided for fun to unofficially fight me y getting up to speed also. The resulting hit was spectacular! Wayne was a great sport for fighting anyways, and they were properly awarded the win because I was never able to legally start the match while not moving.