So today we were driving the robot and at one point one of the motors stopped rotating. After checking each wire, we found that the motor controller was keeping the motor from rotating one direction but not the other. We replaced the motor controller and the problem was solved. Why does this happen? I would like to make sure it doesnt happen again in the middle of a competition.
Basically, you fried one of the 2 H-bridges inside the motor controller (1 for each direction). Only real way to reduce the risk of this is to wire your robot carefully, taking special care to minimize the likelihood of shorts developing where wires enter motor casings.