Transformer Connection Grooves

i think that explains better

http://en.wikipedia.org/wiki/Vector_group

http://www.buloxpower.com/354E54F6-6534-43E9-8935-3AE197387430/FinalDownload/DownloadId-4E802D243374EB9518FBEB9E13B85067/354E54F6-6534-43E9-8935-3AE197387430/UploadedImg/Vector%20Groups.pdf

Digit 0 =0° that the LV phasor is in phase with the HV phasor

Digit 1 =30° lagging (LV lags HV with 30°) because rotation is anti-clockwise.

Digit 11 = 330° lagging or 30° leading (LV leads HV with 30°)

Digit 5 = 150° lagging (LV lags HV with 150°)

Digit 6 = 180° lagging (LV lags HV with 180°)

If you want to know transformer connections meanings please visit link below:-

http://wp.me/p4x8s7-d

how the numbers o,1,5,11 comes in is simply the angle divide by 30 degrees so it starts from o, 30, 150, 180 and 330 degrees angles

All these even angles are so boring in transformers. What about Zig-Zags with unequal voltages to get something not divisible by 30. These have even been made with a LTC mechanism to "wag the tail" and create a transformer which can change phase angle. Then there is always the "Heptner Connection" for those of you who are bored that gives a neutral inside a delta winding. Try to find those on Google. Good luck.

Never seen or heard of a Heptner connection.

and Google wasn't my friend ....

You will never find it on Google, many items are not found on google, which is why we still need books, the old printed type. A Heptner connection is a set of windings connected together, with a conventional zig-zag imbeded in a conventional delta, hence the neutral. By playing around with order of windings on a core-form transformer about any needed combination of impedances can be obtained. It is a valuable transformer for some utility connections, but I have never seen it used in industry. On normal balanced loading it works very much like a conventional delta to whatever. On zero sequence loading it has very interesting results depending on how it is wound, since the zig-zag becomes the primary load carrying winding on unbalanced loads. Depending on design, the zero sequence impeadance can be much higher or much lower than the normal impeadance. The more conventional application in use is to use two transformers, one a delta and one a grounding zig-zag, but it is more economical to combine this in one core and connect the windings together. The problem is that the transformer must be a hand-design since there are not enough made to write computer programs for it.