Need help finding control transformer for 660V system.

[Kiljoy]

One of our dealers is asking for an up-charge for a machine that will connect to a 660V supply. The only information we have from him is that it’s somewhere in the middle east. This is a two part question:

1. Who uses 660V 3 phase systems?

2. Where can you find control transformers that will handle 660V? I’ve done the typical Google searches and have not had much luck short of random Chinese companies that look shady. Sola-HD said they would make a custom one if we bought 100+ units. I only need one!! I even considered using a 3ph. DC supply for all of the controls, but none of them go high enough on the input side. Any thoughts??

 

[ScottyUK]

In Europe 690V is becoming common as an intermediate voltage level for drives which are really too big for the 400V system and too small to justify a 3.3kV system. A 690V control transformer is likely close enough to 660V if you want to avoid a custom type.

Siemens SIDAC range actually has a few tapped at 690V and 660V.



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If we learn from our mistakes I'm getting a great education!

 

[rbulsara]

Are you sure that there is no typographical error and it is not meant to be 600V or 6600V?

600V nominal is intended to be used on 575V equipment. It is possible that some one taking 600V literally and adding 10% margin on top of it.

You can always get a custom built unit and it will cost you but certainly not have to order 100 units. Just Google transformer or reactor manufacturers in your area.

Rafiq Bulsara

http://www.srengineersct.com

 

[LionelHutz]

Try Hammond Power Solutions or Rex Power Magnetics.

 

[burnt2x]

A 380V/110 VT connected line to neutral will do it! If you have the neutral available, that is.

 

[Kiljoy]

I thought about using the neutral, but have no idea of the end user's power system. I've found 380/660V motors, so I know it's correct. I'll look into the 690V transformers.

 

[ScottyUK]

Oh, Middle East... check the supply frequency!

Saudi is 60Hz, most of the rest is 50Hz if my memory is correct: it makes a big difference!

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If we learn from our mistakes I'm getting a great education!

 

[Kiljoy]

I'm still waiting on confirmation of the frequency. I found a transformer supplier that will make me a custom one. Thanks all!

 

[electrolitic]

Kiljoy
Try to combine two transformers, primary in parallel, secondary(440 V + 220 V) in series, addictive polarity.
I did it in the past to replace a failed 1,0MVA 3,3/0,750 kV transformer for a coiler DC converter by two 1,0MVA 3,3/0,460kV transformers. Of course, I needed to open the star connection of one of them to get 06 bushings and adjusted the primary taps. It worked for long time.
Regards from Brazil.

 

[electrolitic]

Kiljoy
Try to combine two transformers, primary in parallel, secondary(440 V + 220 V) in series, addictive polarity.
I did it in the past to replace a failed 1,0MVA, 3,3/0,750 kV transformer for a coiler DC converter by two 1,0MVA, delta/star, 3,3/0,460kV transformers. Of course, I needed to open the star connection of one of them to get 06 bushings and adjusted the primary taps. It was an emergency but it worked for long time...
Regards from Brazil.