Delta/Star Connection

In any case, consult the original equipment manufacturer's [OEM] manual before doing anything. It depends on what is on the front of the circuit. The OEM's manual should be able to advise.

• If it is a bridge rectifier and the outlet is galvanically isolated from the inlet, no problem. Just connect all three phase terminals together and to one leg of the 220V and the star point to the other leg.
• If it is some form of transformer or the outlet is not galvanically isolated from the input, then and don't do it, Ethel. You will blow either it or someone nearby, or possibly both, to Kingdom Come!

Danger!

You MUST NOT connect parallel the three primary coils of a three-phase transformer! You can use any of the three single winding alone, it will work but the available output power will be less.

Thank you Horrible Old Bat,i have seen the manual but it's all written in german but there are connection diagrams which are also not very clear to me.For the 3phase/400v the output of the connection terminals are linked and it is from here that the three cables are taken to the input of the 3phase transformer.According to the diagram the 230v connection is achieved if the link at connection terminal is removed because it is labelled as 3phase/230v.My problem now is how i can connect it to a single phase 230v supply.The name of the product in discussion is nuovaelettra there website is www.nuovaelettra.it,just in case you wish to refer.

Is there someone who knows German in your part of the world?

Have you contacted the equipment manufacturer for a manual in your own 'Mother Tongue'? Most manufacturers are as helpful as they can be at this sort of thing.

I must say that I see no possible correct way to connect this to 220 volt single phase without a transformer replacement. Even then I doubt it as the reason for having 3 phases in the first place is because you want a high power charger....!!

My best offer is if you scan in all the documents i will send you my email address and send them to me, I am an electrical engineer and I live in Germany, but do not expect a positive answer!! I think that it will just confirm what I have already said....

Some of the advice you have been given already is wrong and some dangerous, some are wrong and dangerous and if you do not know which is which, you could end up dead or worse....

My second best offer is for you to sell it and buy a properly designed single phase charger....

That is the best idea of all.....

Hello,

Be careful, if it is a big battery charger, than it is possible that the internal rectifier is also tree phase. In this case, you must use a tree phase supply, otherwise the output current will not be equal enough, and there will be a lot of 'noise' on the DC side.

You can't use the charger on a one phase supply 230 VAC because it will not give you the same output tension. In a tree phase system, the output voltage is 1.73 times higher.

The current you need through the rectifier will be a lot higher because you use only 4 in stead of 6 diodes. And the capacitor or coils normally placed behind the rectifier will be too small to eliminate the voltage differences on the DC side.

I have not seen you application, but it is possible that these problems are going to occur.

Thanks rudy,i was just avoiding the cost of running a three phase supply for this purpose as my location has only a single phase 230/240v suply.

Have you already considered a 3-phase converter? It will run off of the 220-240 volt single phase, and has windings that are phased for 3-phase output, like a generator. The first two wires are the standard input phases, with the 3rd phase generated by the internal motor windings. Then, if a different output voltage is required, a standard 3-phase transformer can step up or down. Just be sure to specify the total load correctly.

Hope this helps.

CJ

I don't think from what u say charger is meant for single phase operation.It should be star connected for 430v 3phase and in delta for 3ph 220v.Perhaps you may aware that there are 3ph 220v supplies in certain countries like Japan for instance.