kb8tq@n1k.org said: > If you go back far enough in time …. there is another alternative: > Big rectifier bank, turning AC into DC, often off of multiple phases > or sources. > Big DC motor running into a fairly large flywheel. > AC generator (or in some cases DC generators) running off of the > shaft I've seen a setup with an AC motor. Also on the shaft was a clutch and diesel motor. The flywheel had to last long enough to get it started. I remember tales of a system having troubles keeping time. It was traced back to a 50-60 Hz converter box that wasn't putting out 60 Hz. Things got better when they gave it a tuneup. That was back in the '80s. It seems strange now that there were power supplies that couldn't handle 50 Hz. -- These are my opinions. I hate spam.