Jim Coleman wrote: > hello all, I've recently moved and now finally have convenient access to a > 220V outlet. I have a Sanyo Denki BL Super servo power supply and amps and > motors from the machine I bought nearly a year ago now, and i really want to > get around to getting them all running. I'm wondering how safe on the power > unit it is to run it off of 2 phase, for both testing and on the machine > running. where the machine is, there is 2 phase service and i have a > home-built rotary phase converter with a 7.5 hp motor. This was built to > run the lathe on, which also has a 7.5 hp motor in it (non CNC) > > For testing, i want to go buy a cord that'll plug into the outlet in the > garage and run the power supply and vfd off of it for testing. > > Would you guys think it'd be safe to try it with only 2 phases? Or should I > reverse engineer the initial stages of the power supply to determine how it > handles the input. I'm figuring it probably just rectifies the 3 phases to > a single DC supply, but im not sure. to my knowledge it's output is 180V, > and the 3 axes are 1.2,1.2, and 2.8KW power ratings, per the mills manual. > for testing, I'll only be playing with 1, maybe 2 amps on it at a time and > no load on the motor shaft except maybe a laser pointer taped onto it. If I > had to, it seems I could put in bigger rectifiers and all to step up the 2 > phases of the input, if thats what it does with it. > > The VFD is a mitsubishi freqrol, i think the spindle is 7.5 hp as well, and > im not sure how often i'd ever hit anywhere near this much power. If anyone > knows where to find documentation for the sanyo denki or mitsubishi stuff, > I'd love to know. I havnt managed to find anything on the net, and the > print stuff i have that looks to be a datasheet for the servo amps is in > japanese. > > thanks for all suggestions and advice > Jim Coleman >
Of course I can't speak to your specific hardware, but in general, IF your equipment simply rectifies the incoming power and stores it in a capacitor, you can run on single phase. There will be significantly more ripple voltage on the capacitor (which may affect downstream circuitry), and significantly more ripple current through the capacitor (which may increase heating and shorten its life). Reducing the load will reduce both of those effects... if you are running at half the design load or less you should be perfectly OK. Some small (low HP) VFDs have the diodes and capacitors sized for single phase input - you'll have to study manuals or datasheets to see if that is true for yours. Minor nitpick: it's called single phase, not two phase. Yes, there are two wires, but they are 180 degrees apart, which means they are really the supply and return of a single phase. Three phase has three lines that are 120 degrees apart. There are "two-phase" power systems, with either three or four wires making two circuits that are 90 degrees apart, but they are _extremely_ rare. Regards, John Kasunich ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
