Transformer Phase Shift
Transformer Phase Shift
(OP)
I understand from IEEE that the high side of a 3p transformer whether delta or wye always leads the low side by 30 electrical deg. (IEEE standard apparently)
I have been told that it is possible to achieve a different angle from a transformer.
I assume this is done by hooking up the phases in a different way. for example(I hope my picture will look ok)
Imagine a normal configuration:
A || A
B || B
C || C
No suppose this:
A || C
B || A
C || B
What is happening here I cannot really understand mathematically. Is there an easy way to evaluate what the actual phase shift will be for a given configuration of transformer windings that might not be in a "normal" configuration?
I'm sure this question is as clear as mud.
I have been told that it is possible to achieve a different angle from a transformer.
I assume this is done by hooking up the phases in a different way. for example(I hope my picture will look ok)
Imagine a normal configuration:
A || A
B || B
C || C
No suppose this:
A || C
B || A
C || B
What is happening here I cannot really understand mathematically. Is there an easy way to evaluate what the actual phase shift will be for a given configuration of transformer windings that might not be in a "normal" configuration?
I'm sure this question is as clear as mud.






RE: Transformer Phase Shift
RE: Transformer Phase Shift
RE: Transformer Phase Shift
Assume
H1-H2 transforms to X1-N
H2-H3 transforms to X2-N
H3-H1 transforms to X3-N
If you connect
A-H1, X1
B-H2, X2
C-H3, X3
You get
V A-B pri transforms to VAn sec
V B-C pri transforms to VBn sec
V C-A pri transforms to VCn sec
For this connection, VAn secondary leads Van primary by 30 degrees.
If you connnect
C-H1, X1
B-H2, X2
A-H3, X3
You get
V C-B pri transforms to VCn pri
V B-C pri transforms to VBn pri
V A-C pri transforms to VAn pri
Now VAn secondary lags VAn primary by 30 degrees.
Same xfmr, but how you connect the phases makes the difference. I believe some companies wish to always connnect phase A to H1 and X1, so they order xfmrs with different internal wiring instead of changing which phase connects to which bushing.
RE: Transformer Phase Shift
V B-C pri transforms to VBn pri
This is a test: What was that supposed to be?
RE: Transformer Phase Shift
The phase shift of multiples of 30 deg. is a characteristic of wye delta and delta wye connections.
There is a phase difference between the line to line voltages and the line to neutral voltages of a wye winding. The delta line to line voltages are in phase with the line to neutral voltages of the wye-delta and delta-wye banks.
If you look at the vector diagram on a transformer nameplate you will see that the line to neutral vectors on the wye side match the angles of the line to line vectors on the delta side.
respectfully
RE: Transformer Phase Shift
We ran into this recently when we brought in a new transformer with a standard 30 degree lag only to find the system was 30 leading. We used the method described by JensenDrive above to correct the 30 degree lead to 30 degree lag without changing the transformer internals.