[Russ Beavis]

I think that Kevin's right regarding double stall current when undertaking a full reversal. For example, if you apply +12V to the motor and get it running at full speed with little torque, the "motor voltage" will be +12V. If you suddenly apply -12V to the motor, there will actually be 24V across the winding - 0V on one motor lead and 12V on the other motor lead but an "internal" voltage of -12V. Specifically, I'm thinking of the standard motor model of resistor + inductor + "motor EMF".

If the motor and load have a large rotational inertia, it could take a while for the motor EMF to reverse direction.

It would be wise to add a bit of filtering to the PWM command to slow down the changes.

For what it's worth, the Jaguar and Victor power stage and heat transfer designs appear to be very similar (ie similar FETs, mounting, arrangement and airflow). Why would Jaguars be more sensitive to full reversal? I'm not sure but I can think of one thing - I wouldn't be surprised if the Jaguar is more efficient. They may be driving their FETs harder and therefore more fully on/off and, as a result, the actual currents to the motor could be closer to the ideal 130A stall currents. However, if they're more efficient, wouldn't that mean less power dissipation? Maybe, but high instantaneous pulse currents can be just as damaging as high power (ie heat output) levels.

Considering the slippery floors, it may be much easier to get to full motor EMFs (not much torque output).

It wouldn't hurt to filter the PWM command to 1) reduce full fast reversal effects and 2) full fast reversal is really "impossible" anyways since you're guaranteed to lose traction.

Russ