5 replies to this topic

[Redskinsdb21]

When you have a transformer, delta-wye, delta-delta, ye delta, wye-wye....

What is the phase shift of secondary voltages and currents after converted to secondary voltage and current values based on turns ratio? Cant seem to find any infp. on this?

[Wildsoldier PE]

I think chapman book explains this...the advantages and disadvantages of each configuration...but im not sure if it was chapman or wildi book

[vskneifl]

Typically the only time their is a phase shift is when you go from a delta to a wye or wye to delta and it is a 30 degree phase shift, a delta-delta and wye-wye will not have a phase shift. It is standard to always have the secondary side lag the primary side but a transformer can be designed to be lagging or leading, for that matter a transformer can be designed to have any phase angle required. Hope that helps.

[Flyer_PE]

In addition to the transformer design, the connections to the system can be manipulated to give you a 30 degree phase shift in either direction.

[DK PE]

It is standard to always have the secondary side lag the primary side...

I thought the ANSI standard that is commonly applied in the US specifies the positive sequence voltage on the low voltage side lags the high voltage side. If you have a step down transformer, your terminology is correct, if it is a step up transformer, you would be incorrect.

Edited by DK PE, 07 April 2012 - 12:32 PM.

[robertplant22]

I'm going to agree with DK PE on this one. My understanding is that the HIGH side will always lead the LOW side by 30 degree regardless of transformer configuration (delta - Y, or Y - delta).

I'm sure this phase shift can be modified for particular applications, but unless otherwise stated in a problem, what DK PE states above is correct.