Which of the following is the most likely source of harmonics in a transformer ?
(A) poor insulation
(B) Overload
(C) loose connections
(D) Core saturation
Iron loss of a transformer can be measured by____________?
(A) low power factor wattmeter
(B) unity power factor wattmeter
(C) frequency meter
(D) any type of wattmeter
Which of the following loss in a transformer is zero even at full load ____________?
(A) Core loss
(B) Friction loss
(C) Eddy current loss
(D) Hysteresis loss
Negative voltage regulation is indicative that the load is___________?
(A) capacitive only
(B) inductive only
(C) inductive or resistive
(D) none of the above
Helical coils can be used on___________________?
(A) low voltage side of high kVA transformers
(B) high frequency transformers
(C) high voltage side of small capacity transformers
(D) high voltage side of high kVA rating transformers
If the supply frequency to the transformer is increased,”the iron loss will__________?
(A) not change
(B) decrease
(C) increase
(D) any of the above
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
A transformer can have zero voltage regulation at______________?
(A) leading power factor
(B) lagging power factor
(C) unity power factor
(D) zero power factor
During open circuit test of a transformer:
(A) primary is supplied rated voltage
(B) primary is supplied full-load current
(C) primary is supplied current at reduced voltage
(D) primary is supplied rated kVA
The voltage transformation ratio of a transformer is equal to the ratio of_______________?
(A) primary turns to secondary turns
(B) secondary current to primary current
(C) secondary induced e.m.f. to primary induced e.m.f
(D) secondary terminal voltage to primary applied voltage