Voltage Transformation

[noxcuses 0]

I have some European equipment that requires 400 Volts AC 3 Phase. My supply voltage is 460VAC 3 Phase. Is there a transformer that has a 460V primary and 400V secondary? Currently, A 230VAC 3ph to 400 volt transformer is used to accomplish this. We are transforming our supply down to 230 then back up to 400 with two transformers.. There has to be a better way to get 400V than that???

[BobB 58]

You will probably have to have one built to your specifications. Pretty common actually - we have to do it all the time in Ozz.

[Duffanator 1]

Check these guys out: www.magspecinc.com They make custom transformers for us once in a while and they make really nice stuff. They are in PA but I'm sure they ship wherever you need.

[TConnolly 13]

They aren't hard to come by. With the thousands of machine tools imported from Europe this is a very common need. We buy a couple every year, mainly ACME transformers. Try this Google search for starters. Edited 21 Oct 2010 by Alaric

[Leitmotif 0]

400 is approx 87% of 460. Bit outside of normal + - 10% on equipment but just gotta ask the question. What is voltage tolerance of the European equipment. Is it possible it may be OK on 460? Dan Bentler

[TimWilborne 108]

I've seen tons of 400V mills and lathes hooked to 460VAC...even a few closer to 500VAC and they ran just fine

[paulengr 44]

After looking at what you said, be VERY, VERY careful when it comes to motors and anything with a coil. Changing from 60 Hz to 50 Hz generally doesn't cause any problems with electronics because it usually transforms to and runs on DC. However, it has major implications for anything with a coil like induction motors. Merely matching the voltage is not enough. As for what the effects are, although there are some calculations you can do, best thing is to contact the manufacturer of the components (not the equipment manufacturer which is usually clueless). The areas of concern will be transformers, motors, generators, and the like. It is possible to do it but in general it usually becomes more cost effective to simply rip out the large equipment (motors, generators, transformers) and replace it with 60 Hz equivalents. One of the problems that you will have is that everything has to be severely derated, like derating it about 15% when you make the change from 50 Hz to 60 Hz. You CAN transform both if you really want to. You could put in a drive and run it at 400 VAC, 50 Hz. That gives you a nice steady power source and "solves" the problem although the reliability of the system will be a little less and you take a 10% haircut on your electric bill. You could also do it the traditional way...use an MG (motor-generator) set where you couple a synchronous motor to a synchronous generator (with a 5:6 gearbox in between). This gets you to 50 Hz, a voltage regulator then drives the generator to control output (usually a DC drive...Siemens Simoregs are very nice for this), and if you want to run it as a synchronous condensor, you can run the synchronous motor as a varcap to regulate power factor for the facility. Downside of course is that again you lose about 10-15% of the energy in the conversion but strangely enough unlike drives (losses are generally a constant), as the size goes up, the losses decrease. I might be the last guy on the planet to even suggest using MG sets but I have 6 of them to maintain in my plant so after the initial revulsion, I got over it and recognized the advantages.

[TConnolly 13]

So have I - if its just a motor and basic controls you'll probably get away with it, but a CNC can be a bit more picky. This is hardly a unique problem - hundreds of companies deal with it every day. Been there done that many times. Just buy a 460 x 380 (480x400) step down transformer from one of the dozens of companies that make them for exactly this purpose and be done with it.