Urgent help required with transformer vector grouping?

[bfarnill75756]

Hi,
I am currently attempting to obtain details in relation to Dy7 transformer. However I am struggling to find any information with regards to the phasing. I appreciate there is 150 degree phase shift, but how is this achieved?
Are there any vector diagrams to illustrate a Dy7 transformer?
Any help would be greatly appreciated.

 

[xnuke]

See the attached image from IS: 2026 (Part 1V)-1977.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[davidbeach]

If a Dy11 has A-phase connected to X1, B-phase to X2 and C-phase to X3 then I believe that you connect B to X1, C to X2 and A to X3. I'm working with a mental picture, could be that I just described a Dy3, draw out the vectors and see what happens.

Starting with a Dy11, you can get a Dy11, Dy7, and Dy3 just by rolling all three phases on one side and by changing the rotation order on both sides and rolling on one side you can also get the Dy1, Dy5, and Dy9.

I think there's a FAQ here about converting the Dy1 to a Dy11 or vice versa. The Basler web site has had a technical paper going into all the various vector combinations, I haven't looked for it for quite a while.

 

[sibeen]

I think there's a FAQ here about converting the Dy1 to a Dy11 or vice versa.

Here's a pdf on doing it that I've posted to this forum a few times.

 

[Marmite]

The context of the question isn't clear, but if you want to see how a Dy7 transformer is connected internally to achieve the 150 degree shift, then see page 19 of the attached document, which is probably the one Davidbeach was referring to. The diagram is lifted from IEC60076-1. If you need to replace an existing Dy7 transformer with a more common Dy1 or Dy11 then you would follow the advice given by Davidbeach.

Regards
Marmite

 

[7anoter4]

It is correct, xnuke. It is the same as per IEC 60076-1 Annex D pos. 7 as Marmite said.