Vector of an old transformer

[Alex68]

Dear Collegues,
I'm dealing with an old transformer, dated 1970, whose ratio is 10 / 0.4 kV.
The vector group is indicated as ynD11.
This is new for me. Is it equal to Dyn11?
What is the connection of the primary winding: yn or D?

Thank you for you help.
Cheers
Alex

 

[Marmite]

It is a little confusing from what you describe. The first symbol is supposed to be the HV winding connection, the second symbol the LV winding connection, and the third symbol is the phase displacement expressed as clock hour number, which would give you Yd11, however the high voltage winding is supposed to be in upper case, and the lower voltage winding in lower case. Add to that the fact that the neutral connection suffix is lower case and attached to a y rather than Y which suggests this relates to the LV winding. If I had to guess I'd go for Dyn11, but to be on the safe side you would have to test it. Does the rating plate have a winding diagram?
Regards
Marmite

 

[RRaghunath]

Alex68,
Was it meant to be Step-up transformer originally, with some generator connected at 400V bus!
If I remember right, the old standard was to represent the primary winding connection in the first letter.
Neverthless, presuming 400V is Star connected with neutral, then ynD11 shall correspond to Dyn1.

 

[Alex68]

Thank you guys.
You confirmed my suspects.
I asked for the photo of the faceplate.
Thank you again.