I understand that transformer losses are a combination of core losses and I2R line losses.
I believe transformer impedance is the combination of inductive impedance (No Loss) and I2R line losses.
If you have a transformer with a high % impedance does that mean anything to you in terms of the efficiency of the transformer? Is a transformer with a 7.5% impedance common?
I have a customer with a Dry Type GE 480 Delta - 240 Delta 75KVA 7.5%Z transformer which is operating too hot to even put your hand on the top center. The installation is only a year old and it is be operating at this temperature since installation. The transformer feeds a single machine, which runs continuously and I am sure it is fairly loaded. Kind of surprised to see 7.5% impedance. I am used to impedances more in the range of 4-6%.