Crusty and the Pulley
RAY: Because the generator was never meant to turn at very high speeds, what he did around town was okay. By making it run faster he did indeed charge up the battery by making the generator think the truck was running at 50 mph.
Except when he got it up to 50, the generator thought the truck was going 100 mph. The commutator -- which is that part of generator with all those slits of copper that send the electricity through the brushes and ultimately to the battery -- flies apart from centrifugal force. The generator self-destructed. He came back with a box of melted mush.
TOM: Hey, he could have used that "commutator" to get his mother's sentence "commuted"!
[ Car Talk Puzzler ]