paper: Window Motor Lockups: Causes and Solutions

[Al Skierkiewicz]

Larry,
I could see that using a right and left motor with the pins in place could lead to some locking of one or the other of the motors when used with either controller. However, I have also seen a number of teams use this configuration for arms without any reported difficulty. In those cases the teams intended that the anti-back drive keep their arm in place. They seemed happy with the performance.
In talking with John Novak who did some testing with these motors, it really does appear that the very low mass of the pins (I believe they are phenolic) can easily be set in motion by the switching frequency of the Jags when the motor is not actually moving.
Gary, I had not considered the self heating at 15kHz of the PTC as an issue. However, I think you may be right. If any teams can give us some more data on this, it would be appreciated.
I am going to guess that this operation takes about fifteen minutes per motor. Would that sound accurate?