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A Problem we didn't know we had until the next season, occurred with the old drill motors, which were fastened to out home-made gearbox using a friction "collar" around the motor. When the demand was made for quick acceleration, we saw later that the motor turned (Thanks three times to Sir Ike). All I heard during the season was "the motor power lleads are _falling_ of by themselves". Once we saw the motors turning as muh as 90 degrees, we saw the reason the leads (using 0.187 spade female QD connectors) were "falling" off. It was decided to mount the Drills using the mounting screw-holes provided on the front end-bell of the motor.
A short to the case or gearbox via disconnected leads, as above, for example, could cause the same high currents Al describes. IFI used to brag about the 883 Victors handling several hundred amps, as a charging robot was put into full reverse, and with three FETs in parallel in each leeg of the "H"-bridge, each capable of carying a coninuous 50 A and more. it would take a verylarge current to blow them before the breakers went.
Some industrial SCR / Triac A.C. power circuits actually use semiconductor diodes as fuses, because they'll blow faster than a fuse.
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