Roger Stockton wrote > Jeffrey Jenkins wrote: > >> Note that there are some controllers without any significant amount of >> input capacitance, like the old GE EV1 and EV100 types, that very well >> could be damaged by interrupting power to them while under load. > > I can't say that it isn't possible to damage the GE EV1 by repeatedly > interrupting power to them while under load, but I can say with certainty > that it is possible to interrupt power to it while under load without > damaging it in the least. I have done this with mine.
Sure, if the semiconductor switch is still conducting (either on purpose, or because it has failed short) then the energy stored in the stray inductance of the battery circuit will be dissipated in the motor. If the switching device has been commanded off or failed open, however, and there is little or no input capacitance, then the battery circuit stray inductance will create whatever voltage is necessary to maintain a continuous flow of current, which basically means the semiconductor switch will be forced on via avalanching. If the battery circuit inductance and/or the current is low enough, and/or the avalanche energy rating of the switch is high enough, then the switch will survive this abuse, though possibly with some long term degradation in current gain for bipolar transistor/SCR devices. In any event, I agree that it is entirely foreseeable that a fuse will blow, a contactor will open under load, etc., but I don't mistake that for being a "normal" or "everyday" occurrence. Generally speaking, you size the fuse to protect the insulation on wires from overheating, so if the fuse blows consider that a none-too-subtle hint. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Inertia-switch-tp4661516p4661540.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
