Steve, of course, you can't very well connect a 120 V transformer to 240 volts without expecting a minor catastrophy (especially considering the power class we are talking about). In the UK, they have generally a nominal 240 volts mains supply (don't know about the tolerances). "On the continent", the better part of europe ;-), we used to have 220 volts +/- 5%, that is, from 200 to 240 volts. Since about 2000, we now have 220 volts +10 / -5% which means anything from 200 to 245 volts. In order to make the most profit of the network, suppliers tend to deliver 237 to 240 volts constantly. So, in effect we are on the same feet now as the British. One wire is neutral (center point of the general three phase supply) and grounded in every transformer station down to the last substation and in every house. In fact, the cable to our house has four 70 sq. mm "wires", and Neutral and PE are first separated in my incoming 50 A fuse box, right before the counter.
No problem exchanging electric equipment between Germany and England. Peter Steve Stallings schrieb: > When selecting a transformer, it is not sufficient > to just get a 1:1 ratio. The core must not be > allowed to saturate. If you take a 120 VAC rated > 1:1 ratio isolation transformer and try to operate > it on 240 VAC it will likely saturate. When the > core is in saturation the normal back EMF does > not develop and the winding will look nearly like > a short circuit. Not a good thing! Going the other > way, operating a winding at less than its rated > voltage, is OK. You just get less than the full > power that the core is capable of handling. > > Steve Stallings > > -----Original Message----- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: Wednesday, September 07, 2011 4:35 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Servo PSU > > On 7 September 2011 07:53, Peter Blodow <p.blo...@dreki.de> wrote: > > >>> Yes, but I can't find one. (or not one rated at 15A / 240V anyway) >>> > > >> Andy, I have one here that will deliver this power easily. It used to >> power a hospital supply where all electrical gear must be floating. The >> only problem would be the shiping since it is very heavy. Where are you, >> anyway? >> > > I am in the UK, and I just realised that I do have a transformer, on > fact I have been using it all along during the development phase, a > safety isolating transformer. > > It is interesting watching this conversation develop, as Pete and Dave > are both of the opinion that what I have is entirely conventional for > a servo drive. > > I have also just noticed that the transformer I rescued from the skip > at work (A 1160VA Siemens one) might work, if I can find a combination > of winding taps that gives 1:1. > > Thanks for the offer, though. > > ------------------------------------------------------------------------------ Using storage to extend the benefits of virtualization and iSCSI Virtualization increases hardware utilization and delivers a new level of agility. Learn what those decisions are and how to modernize your storage and backup environments for virtualization. http://www.accelacomm.com/jaw/sfnl/114/51434361/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
