On Saturday 13 June 2015 13:20:19 Ken Strauss wrote: > Aren't these often auto-transformers which provide no isolation > between input and output?
Thats what I am careful to check. The one I bought is two separate 120 volt windings according to the label. And I may unwind a few turns from the one I use as the secondary. The fw bridge rectified output needs to lose 25 volts to be about right. No biggie. Worst problem is that it weighs a hair north of 22kg. 28 shipped. > > -----Original Message----- > > From: Jon Elson [mailto:[email protected]] > > Sent: Saturday, June 13, 2015 10:53 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Suitable transformers = hens teeth > > > > > > There are, however, "step down" transformers. These usually have > > split primary and secondary windings, so you can configure them for > > 240 or 480 V on the primary, and 240 or 120 on the secondary. If > > you can tolerate > > running > > > it at half voltage, set primary for 240 V and supply 120, and then > > you can > > get 60 > > > V AC out of the secondary. Or, get 120 V CT on the secondary and run > > through > > > a 2-diode full-wave rectifier to get about 84 V DC with a capacitor > > input > > filter. That would be a bit light of ideal but probably usasble. I usually use a fw bridge, its its less ohmic heating in the transformer. Details... ;-) > > You can find these in the multi-KVA size. Often machine tool > > vultures and industrial surplus places have PILES of them. Which they don't seem to list on fleabay. > > Jon > > ---------------------------------------------------------------------- >------ -- > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ---------------------------------------------------------------------- >-------- _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users 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
