On 1/4/22 10:04 AM, Paul Koning via cctalk wrote: > The other option, typically somewhat more expensive but cheaper than an > 11/780, is a rotary converter. Those are 3 phase motors, sometimes modified > a bit, driven from single phase power that construct the missing phase > somewhat like a dynamotor would. Those things produce proper sine waves so > they are good to use even with things that are picky. Rotary converters can > be found in machine tool supply catalogs.
One has to be careful here. The common "idler" type of rotary converter uses a 3-phase motor, with only one set of windings fed from the single phase supply and leading the third phase idle to develop a current that's +/- 90 degrees from the powered phase. So the output looks like 0,90,180, rather than 0 120 240 degrees. Good enough for powering a 3-phase motor with slight derating, but nothing I'd use to power a computer power supply. The second type is similar, but incorporates a dual field arrangement, with a single-phase field coaxial with a 3-phase one comprising a motor. You get much better output phase relationships there and one would probably work fine with a computer. --Chuck
