Progress on new shop

On Apr 26, 2014, at 06:58 , Paul Koning <paulkoning at comcast.net> wrote: I use a rotary phase converter for my milling machine and lathe. I haven't scoped out the waveforms myself, but I got the impression from the guy who I got the machines from (who's in the machine shop business) that rotary phase converters don't make especially clean power. Two of the three legs are simply connected to the single-phase AC supply, and the converter generates the waveform for the third leg. I gather that both the amplitude and phase of the third leg vary widely from the nominal preferred values, especially as the load impedance changes. It's good enough to make a 3-phase motor spin the right direction, but maybe not so great for a single-phase electronic load powered from that leg. So, for a computer that normally takes 3-phase power but actually just has single-phase loads internally (i.e., it's made to take 3-phase power since that's what's available in industrial/commercial buildings, but nothing in the machine actually requires 3-phase power), I think that a single-phase conversion might be preferable to using a rotary phase converter. I think an electronic 3-phase converter with clean sinusoidal output would probably work just fine, though, in cases where the machine actually needs 3-phase power and/or you just don't want to modify the machine at all. I'd like to look into getting a big solid-state converter for my workshop, but it hasn't bubbled to the top of my list yet. -- Mark J. Blair, NF6X <nf6x at nf6x.net> http://www.nf6x.net/