transformer design

[Rajan Shakti]

hi folks,
i need ask a design concept for a delta star transformer 25kva my incoming is 480vac 3 phase and 415 vac 3 phase i want to use it one at a time for three incoming voltages 191 240 and 415 vac can anyone help me with the winding do the transformer has two separate primary winding for two different type of voltages

 

[stef]

Are you going to wind this transformer yourself? Give the details to a transformer manufacturer, they will do the design for you and make that thing to spec. Don't know whether you are UK based or not, if you are ask Majestic Transformers in Poole, they can help you. Not that I am advertising for that company, but they know what they are doing.

 

[stef]

The transformer you are after doesn't have to have two separate primary windings, a set of three primary windings with several tappings for different primary voltages.
For each purpose the transformer windings have to be reconnected to match the primary voltages in delta connection.

 

[Rajan Shakti]

ok,lets say the transformer getting input voltages 380-400-440-480-660-690 V and out put is 230-440 v,the tappings provided for the incoming voltages but the incoming will be the same connection either it can be of any voltages,how can it be done by the use of relay and contactors for different set and range of voltages without any manual selector switch

The transformer you are after doesn't have to have two separate primary windings, a set of three primary windings with several tappings for different primary voltages.
For each purpose the transformer windings have to be reconnected to match the primary voltages in delta connection.