[Matt Krass]

Originally Posted by EricVanWyk

The two factors to consider are the magnitude and duration of the current. Many fuses are rated in terms of amp squared seconds.

There are several common situations that accidentally bypass a circuit breaker OR uses the wrong circuit breaker. These allows the same magnitude but longer duration current pulse.

There are also weird ones where the wiring includes a pathologically bad amount of resistance. These allow a low magnitude but long duration current pulse. In this case, the crowbar might be able to protect its owner until it burns itself out.

Ah, I did consider that, but I was under the impression that in this situation it wasn't relevant because in the event of a reverse power connection to the controller, my experience has been that it short circuits in the same manner as the crowbar and causes the same metronome of breaker popping. I admit I haven't (yet) taken the measurements, but my general hunch was that the crowbar solution was no worse on the system regarding violent current pulses of varying duration than the existing problem, but it would spare the controller. The only added concern I saw was buildup of heat on the diode, but I figured with a proper heatsink on a diode designed for 100A whacks, it's probably safer than the tiny components in the Jag absorbing the hit.

I appreciate your input, these types of discussions are always fun, do you have any more thoughts on my theory?

For the record, I was working with this guy for the test:
http://www.st.com/internet/com/TECHN...CD00077607.pdf

Matt