[jcarr]

I often see robots disconnect from Samantha after a collision or pushing contest. Often it is because a connection is jarred loose temporarily (usually the Molex battery connector) or another wire.

However, the way the motor controllers work is that if you tell it to go forward, and the wheel can't turn, it increases current to the max 4 amps, regardless of what you told it to run at. You will see the battery drain quickly and the motor will burn out if you continue for more than 1.75 seconds. That can also cause disconnects and you may see the NXT freeze. You will smell the motor.

PS - a lot of the time the motor is only singed - it will still run, just at reduced power. If you are on a limited budget, like we are, we continue to use the singed motors, although we may switch them to an arm.