Running 3 phase 780s on single phase power (was RE: hams on classiccmp)

Ian> Um, let's clarify something: there are NO three-phase components Ian> in a VAX-11. The switchers, the fans, ALL of it are single Ian> phase. Oh, there is one component that's "three phase": the Ian> power supply in the PDU itself, which generates the voltage to Ian> run the relay that switches the switched outlets. That's fused Ian> separately. And yes, the neutral leg has a breaker, too. Ian> And yes, this IS a "full config", with RH780, DW780, CI780 and Ian> (lucky us!) FP785. Some peripherals are real three phase, though; the RP06 comes to mind. A breaker in a neutral is odd. I guess it's legal IF it's part of a set of tied-together breakers, so that tripping the neutral breaker also opens the phases. I wonder why they didn't use 3-phase power supplies; that would save space for the filter capacitors. paul