[williamson]

Thanks for your reply. Boy, do I have a lot to learn. I never thought of all those reasons. This is the place to learn. I have another idea: starter relays will arc to failure on high voltage DC OR inductive loads. What about the controller commanding 4 external starter relays(a bridge, at the motor cables or battery?), to accomplish "power on-off", (regardless if the driver has a manual circiut-breaker by his right hand), just the usual "power-off-on", and reverse, without an expensive reversing 1000 Amp contactor? The magic would be that the controller could precharge with a MOS-FET. No inductance in a resistor, and inherently fixed current drain. Then after precharge, where the voltage drop is zero, the appropriate relays could close.The controller would wait in the "traction MOS-FETS off" mode, until the relays had kicked in. Also reverse would be "Motor off" switching(as usual). When I talked to the Warp-9 engineer, he said they were going to implement dRPM/dT, to forstall the eve of destruction, exactly as you suggested. Right on! Kindest regards to all, willaimson