Transformers

If a transformer is switched on to a voltage more than the rated voltage______________?

A. its power factor will deteriorate
B. its power factor will increase
C. its power factor will remain unaffected
D. its power factor will be zero

Open circuit test on transformers is conducted to determine____________?

A. hysteresis losses
B. copper losses
C. core losses
D. eddy current losses

Part of the transformer which is most subject to damage from overheating is_____________?

A. iron core
B. copper winding
C. winding insulation
D. frame or case
E. transformer tank

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

A no-load test is performed on a transformer to determine_______________?

A. core loss
B. copper loss
C. efficiency
D. magnetising current
E. magnetising current and loss

Which type of winding is used in 3 phase shell-type transformer?

A. Circular type
B. Sandwich type
C. Cylindrical type
D. Rectangular type

An open-circuit test on a transformer is conducted primarily to measure______________?

A. insulation resistance
B. copper loss
C. core loss
D. total loss
E. efficiency
F. none of the above

The transformer lamination’s are insulated from each other by____________?

A. mica strip
B. thin coat of varnish
C. paper
D. any of the above

When secondary of a current transformer is open-circuited its iron core will be__________?

A. hot because of heavy iron losses taking place in it due to high flux density
B. hot because primary will carry heavy current
C. cool as there is no secondary current
D. none of above will happen