Answer / ravi

Winding connection designations

High Voltage Always capital letters
Delta - D
Star - S
Interconnected star - Z
Neutral brought out - N

Low voltage Always small letters
Delta - d
Star - s
Interconnected star - z
Neutral brought out - n


Phase displacement
Phase rotation is always anti-clockwise. (international
adopted convention)
Use the hour indicator as the indicating phase displacement
angle. Because there are 12 hours on a clock, and a circle
consists out of 360°, each hour represents 30°.
Thus 1 = 30°, 2 = 60°, 3 = 90°, 6 = 180° and 12 = 0° or
360°.
The minute hand is set on 12 o'clock and replaces the line
to neutral voltage (sometimes imaginary) of the HV winding.
This position is always the reference point.
Because rotation is anti-clockwise, 1 = 30° lagging (LV
lags HV with 30°)and 11 = 330° lagging or 30° leading (LV
leads HV with 30°)



To summarise:
Dd0
Delta connected HV winding, delta connected LV winding, no
phase shift between HV and LV.
Dyn11
Delta connected HV winding, star connected LV winding with
neutral brought out, LV is leading HV with 30°
YNd5
Star connected HV winding with neutral brought out, delta
connected LV winding, LV lags HV with 150°


" So there is no specification of Dy11.. it will be Dyn11 "

Answer / pb

Dyn11 means Primary---Delta, Secondary---Star with neutral
brought out and secondary leading the primary by 30 deg

In case of Dy11 --- neutral is not brought out, rest
remaining the same as above.

Answer / sunny

thanks ravi
i had searched all over the net but didn't cleared myself.....
very easy & understanding

Answer / jim kirk

Mr Ravi

An excellent explanation - but there are DY11 transformers - we have two of them onsite

Answer / kandavel .p

Thanks Mr Ravi i understood clearly ,your way of explanation is good thanks lot

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