Transformer gauge at -7.6 PSI - causes?

I have a 2500 KVA transformer, 12,470 V to 480 V Delta to Wye which was showing a negative 4 PSI vacuum with the guage needle bouncing noticeably. It is now showing negative 7.6 PSI.

The temperature has warmed up and the pressure should have gone closer to 0 rather than further to the negative.

I am concerned there may be a leak which could contaminate the oil in the tank. If there was a leak the pressure should have gone closer to 0.

The transformer is operating at approximately 2800 Amps and the maximum Amps is 3008 so 93%. Outside temperature was plus 8 C.

Are there any thoughts on this situation our there?

Any information would be appreciated.



Senior Member
Westminster, MD
oil testing

oil testing

I think that could be arcing in the tank that's causing oxygen depletion and a corresponding vacuum.
I recommend you have the oil tested as soon as possible.