GETCO Exam Paper (30-11-2008)
In a transformer it is difficult to measure the efficiency by output-input measurement methods because

the output is sinusoidal and hence cannot be measured
efficiency of transformer is usually high and hence extremely accurate measurements will be necessary
losses are abnormally high
output is out of phase with respect to input

ANSWER DOWNLOAD EXAMIANS APP

GETCO Exam Paper (30-11-2008)
A buchholz will operate in a transformer whenever there is

any of the above
saturation of magnetic circuit
large internal fault
over load

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP
MORE MCQ ON GETCO Exam Paper (30-11-2008)