On Friday 12 June 2015 23:02:32 Gene Heskett wrote: > On Friday 12 June 2015 22:06:16 Jack Coats wrote: > > Yes Gene, there is no santa clause, especially when you are talking > > about copper. Just as a raw material it is pretty pricy. > > > > In the past I just got a couple of matched transformers 120VAC to > > whatever, and put the secondaries together. > > It makes a good isolation transformer when set up back to back. > > At double the iron & I2R losses though. I'd druther have it on one > core. > > > Good transformers are never cheap. > > Depends. When Peter Dahl was winding stuff for us broadcasters 20 > years ago, I thought he did a quite reasonable job of selling me a > modern, grain oriented steel core replacement that was 1/2 the size of > the original that smoked, the smaller size made possible by the > improved steel for laminations compared to what was in the originals > in 1956, when I needed it in 1999. I fully expected to have to pay > twice what he asked, considering he was winding it from scratch using > the old GE drawings. And he had it on site in 4 days! > > I am well aware of that lack of a Santa Jack, but we're talking about > a couple kilowatts worth of iron & copper to have a CCS rated setup. I > don't mind paying some north of a $150 bill, but even at that, the > selection on fleabay is limited, or poorly described. One 1.5kw > toroid looked promising, but the guy may be blowing smoke, no way to > tell from his description. I might send him a msg tomorrow to see if > he has any more data on it. Good sized, weighs in just short of 40 > lbs, so I don't doubt the 1.5KW rating. But the windings description > is sorely lacking in details. > > Heck, something out of an old microwave wound on an EI core could > probably have the high voltage winding recycled & replaced with 8 > gauge enough for what I need. Some stepdown, say 25-30% would be ok > as I'd like to have about 105-110 volts out of a bridge rectifier into > a 75,000 uf cap or 2. Those I have several of already. Surge rated > at 150. They seem to tolerate the back dump into the supply when > slowing that 1 hp motor ok. > > If I sounded like I was looking to get lucky I'm sorry. > > > On Fri, Jun 12, 2015 at 6:09 PM, Gene Heskett <[email protected]>
And I may have found one I can use, now if ebay would just let me login. &^#@*&*(+ > > wrote: > > > Hi all; > > > > > > In laying out how I am going to cnc this GO704, its apparent that > > > the scr or triac board it comes with to control a motor of > > > undetermined power, rated variously as 750 watts, 1kw, or needing > > > 12 amps from the line. None of which groks, but welcome to chinese > > > specs seems to be the operative response. :) > > > > > > Anyway, since Jon's pwm servo amplifier worked so well on my > > > lathe, and its theoretically capable of that sort of power (20 > > > amps at 160 volts IAACS), my mind is made up to use it again. But > > > its I/O is not all isolated so it must have an isolated power > > > supply. > > > > > > But 1kw and up isolation cans are both scarce, and north of a $100 > > > bill pricy at least on fleabay. > > > > > > Has anyone got something laying around getting dusty that could > > > serve as a 120 to 120, or 240 -> 120 isolation, and that you might > > > be able to part with? I have 240 just 7 feet away from where I > > > have it parked so a stepdown would work just as well and would > > > help balance the load. > > > > > > Send me PM's with what it is & how much you'd need and lets see if > > > we can deal? > > > > > > Thanks. > > Cheers, Gene Heskett Cheers, Gene Heskett -- "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> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
