The efficiency of transformer is maximum when

A transformer has negative voltage regulation when its load power factor is

The function of oil in a transformer is to provide

The open circuit test in a transformer gives

A delta/delta connected transformer is connected to V/V connected transformer. The ratio of VA rating of V/V connected transformer and delta/delta connected transformer is

In transformer, bushing failure occurs due to (i) transformer vibrations (ii) dielectric losses (iii) partial discharge

A transformer transforms

The efficiency of an ordinary transformer is maximum when

Transformers are rated in kVA instead of kW, because

The efficiency of a power transformer is around