Delta/Star transformer question

Thread Starter


Joined Jul 17, 2010
can any body help me .I have rewound a three phase 15 kva 415/115 delta /star 4 wire transformer .windings are identical for each phase HT turns is 216T 12SWG round wire and LT 60 T 7 SWG wire .LT side is star connected and neutral is taken. My problem is I am getting about 10 V between neutral and body of transformer .input voltage 415 volt has negligble diference in line seccondary is perfect 115V . How this neutral voltage come is there any remedy to suggest.
hope some body can solve this problem. the transformer is used for special purpose where the system demands less than 3 V leakage between Neutral and earth.
plse help


Joined Aug 29, 2009
Are you saying the secondary windings and neutral are completely floating, and you are connecting a meter between the neutral and core? Is there an earth connection to the core? Do you have a Tx earth screen? Have you megger and flashed the transformer to test insulation?

Ciao, Tim