Transformers

Which of the following is not a routine test on transformers ?

A. Core insulation voltage test
B. Impedance test
C. Radio interference test
D. Polarity test

An ideal transformer will have maximum efficiency at a load such that?

A. copper loss = iron loss
B. copper loss iron loss
D. none of the above

A transformer can have zero voltage regulation at______________?

A. leading power factor
B. lagging power factor
C. unity power factor
D. zero power factor

Noise level test in a transformer is a______________?

A. special test
B. routine test
C. type test
D. none of the above

In an actual transformer the iron loss remains practically constant from no load to full load because:____________?

A. value of transformation ratio remains constant
B. permeability of transformer core remains constant
C. core flux remains practically constant
D. primary voltage remains constant
C. secondary voltage remains constant

The path of the magnetic flux in transformer should have____________?

A. high reluctance
B. low reactance
C. high resistance
D. low resistance

When a given transformer is run at its rated voltage but reduced frequency, its____________?

A. flux density remains unaffected
B. iron losses are reduced
C. core flux density is reduced
D. core flux density is increased

Which of the following properties is not necessarily desirable for the material for transformer core ?

A. Low hysteresis loss
B. High permeability
C. High thermal conductivity
D. Adequate mechanical strength

The leakage flux in a transformer depends upon______________?

A. load current
B. load current and voltage
C. load current, voltage and frequency
D. load current, voltage, frequency and power factor

An ideal transformer is one which has_____________?

A. no losses and magnetic leakage
B. interleaved primary and secondary windings
C. a common core for its primary and secondary windings
D. core of stainless steel and winding of pure copper metal
E. none of the above