On Friday 13 December 2013 09:07:06 Gregg Eshelman did opine: > On 12/12/2013 3:26 PM, Leonardo Marsaglia wrote: > > 2013/12/11 Dave Cole <linuxcncro...@gmail.com> > > > >> It sounds like you are greatly simplifying the machine. An MG set > >> (motor generator set) is a very old technology to create DC power. > >> That was probably obsolete when it was installed. > >> > >> Yes indeed, I really don't understand why a 70's machine would use an > > > > motor generator to feed a DC motor. > > For the early variable speed DC motor drives, Monarch and some other > lathe manufacturers used a 3 phase AC motor driving a DC generator to > power the DC motor. > > There have been more than a few people hook those up to rotary phase > converters. > > Single phase AC motor driving a three phase AC generator, powering the > three phase AC motor, driving a DC generator, powering the DC motor.
Such complexity in big iron is crazy, and crazy expensive too, if your hp requirements are reasonable. Empire electric, someplace in WI, can sell you a 0-10 volt analog input control for a dc motor, runs on the 127 volt powerline, and can deliver 25 amps if your circuit breakers can, all for about $150. Needs about 2.5" of height above a nominally 6x6" open frame plate, which is grounded. Hide it anyplace handy. That will power a honking big 4 or 5 hp treadmill motor (see ebay) cleanly, cool & absolutely silently. All in ultrsonically switched hexfets, so essentially zero heat. These motors aren't "dressed for the party" but appear to have only one failure mechanism, worn out brushes. They are quite good sized, so that will take quite a while. Laying on the table turning 10k or more revs, you can't hear anything but the fan pulling cooling air. I have one running a 1.5hp treadmill motor with a 9 amp circuit breaker that has only been tripped a couple times, I had miss wired one of my ice cube relays. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> Help! I'm trapped in a Chinese computer factory! A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
