!!!DANGER!!! !!!WARNING!!! Exploding A/C clutches!!!!

I retrofitted a 1990's era Mazda MPV (had been an Alaskan rental car) with a complete A/C system from a junkyard. Before getting it charged, I bypassed the low-pressure safety valve to see if the compressor would kick it. It kicked in alright, for a few seconds, then locked up. Spent a couple hundred dollars more for another compressor, then everything worked as it should. Assumed I destroyed the compressor, probably did.