With the transformer in the charger ensure it has been designed with 50 and 60 Hz in mind or it will get too hot (typically 60Hz transformers are 10% smaller) but are designed for the same temperature rise. Auto transformers are available for 3 phase we use an one rated at 80 kva step up and down by 15% its about the size of a 20kva. UK mains is specified at 400V +10% -6% (415)according to G5-4 until unification of Europe at 400V +6% -10% (380) the final European voltage should be 400V +- 6% Rgds Steve Battery charger/UPS manufacture Bristol England www.pbdesign.co.uk -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Spehro Pefhany Sent: 04 April 2006 18:23 To: Microcontroller discussion list - Public. Subject: Re: [EE]: 3 phase transformers At 11:20 AM 4/4/2006 +0300, you wrote: >On 4/4/06, Sean H Breheny wrote: > > Hi all, > > > > I have some high-power battery chargers which run on 480V 3 phase > power. I need > > to be able to make them work in England, where I believe the standard 3 > phase > > service voltage is 410V (please correct me if I'm wrong). > > > > These chargers can handle 50Hz instead of 60Hz, but they cannot work > down at 410 > > V. So, I need a transformer which takes 410V and gives me 480V. > >Sean, not a transformer but a self-transformer (autotransformer). >Will be smaller and cheaper. For single-phase transformers called "buck-boost" are sold for this kind of small adjustment of voltage (and of course they have a relatively small and light size for the total output power). I don't know if 3-phase types are available or if you'd have to use three of them. An industrial electrician should know (sounds like a forklift battery charger or something of that ilk). Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist