On Tuesday 10 December 2013 14:55:24 andy pugh did opine: > On 21 October 2013 18:21, Les Newell <les.new...@fastmail.co.uk> wrote: > > A trick to get around this is to use a 24V transformer to buck the > > mains down to 216V. Add the voltage doubler after that and your DC is > > spot on. > > You seem to understand transforners :-) > > I am wondering what I can do with this one, that I found in a skip. > > Ideally I would like a 100V isolated supply, just to be a bit less > scary when messing about with servo motors. > (Rectified UK mains is 300V + ) > Or about 215 volts rms, 50hz I assume?
> This is the label on top: > https://drive.google.com/file/d/0BxjJW1-T6n7Cd2FrOWV5R3dRZnFhV2xrV0F3OHp > 3UW05X2NF/edit?usp=sharing This label can be a bunch ambiguous. But with the top wired in parallel, feeding one side to terms 39 and 37, and the other side to 36-38, one would assume the secondaries can then be probed to see which could be used to obtain the voltage you need. Basically two warnings apply. Don't "seriously" overvoltage the primary else the iron will become saturated magnetically at the peak voltage and when that happens the input current rises dramatically and heating destruction can occur. I see it has a 1050VA rating, or nominally 1 kilowatt in round figures. The iron saturation point isn't a generally published spec but can usually take a 15 to 25% overvoltage condition in well built transformers. I ran my mill for years on an old tranny from a 2" tape machine, feeding the 127 volt primary voltage we get here in the US of Hay, to the primary terminals labeled for a 90 volt feed, in order to get 29.5 volts for the motors out of the 24 volt winding when using a choke input filter. No noticeable heating of that 50+yo well potted hunk of iron, but that is "pushing the envelope" looking for the smoke vent with more modern iron. This transformer in the pix, can also handle a nominally 440 volt feed by shorting 37-38 together, and feeding the line rails to 36 & 39. This would divide the secondary voltages by 2. They could have labeled it better though, and I doubt if an English label would remove any of the ambiguity. If that was available as surplus, I'd take a couple of them. 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> Better dead than mellow. 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
