Trainer, no problem. I have yet to see how the AC motors hold up. If they hold up better, great!
The only high commutator bars I have ever seen from bulldozing are always on a 4 wheel sit down. The reaches, pallet jacks, tuggers, will spin the tires. The 3 wheel sit downs that have two drive motors just don't seem to raise a bar. I suppose it is because the current is distributed to two motors.

My co worker and I saw a new Raymond pallet jack that was AC drive. We both had the same thing on our mind: this is a sales gimmick in a pallet jack. The brushes in the drive motor are so easy to change in a pallet jack that the savings in maintenance of having the AC motor is insignificant. Most all DC drive trucks have seperately excited field windings now. The motors run cooler, and there are no forward and reverse contactors. There is also no need for a re-gen braking or field weakening contactor. There are seperate transistors in the controller for the field and armature windings. There is no fan on the controller running all the time like I see on most AC motor controllers.

This is an interesting discussion, but the guy who originally posted the question has not posted again. Did we answer his question?