[EricH]

Originally Posted by Chris is me

The Tetrix motors don't have a fuse - what are you talking about?

Originally Posted by <R92-C>, as amended by TU#5

no more than one 12V rechargeable NiMH battery pack identical to those supplied in the FTC kit of parts (PN W739057) except the 20A fuse may be replaced with an equivalent type of lower amperage,

OK, so it's the battery. But it's the motor part that is the problem, as noted in this sentence from the same Update: "Additionally, it has come to our attention that teams have burned out their Tetrix motors by stalling them while directly connected to the battery."

The motor has a part that lets the smoke out at about 20A. As such, teams are encouraged to replace the fuse on the battery pack or use the thermal protection wiring (allowed later in the rule as updated in TU#5).