A no-load test is performed on a transformer to determine_______________?
(A) core loss
(B) copper loss
(C) efficiency
(D) magnetising current
(D) 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
(D) 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
The efficiency of a transformer, under heavy loads, is comparatively low because_______________?
(A) copper loss becomes high in proportion to the output
(B) iron loss is increased considerably
(C) voltage drop both in primary and secondary becomes large
(D) secondary output is much less as compared to primary input
The maximum load that a power transformer can carry is limited by its________________?
(A) temperature rise
(B) dielectric strength of oil
(C) voltage ratio
(D) copper loss
The hum in a transformer is mainly attributed to______________?
(A) load changes
(B) oil in the transformer
(C) magnetostriction
(D) mechanical vibrations
The efficiencies of transformers compared with that of electric motors of the same power are____________?
(A) about the same
(B) much smaller
(C) much higher
(D) somewhat smaller
(D) none of the above
The transformer oil should have _______ volatility and _______ viscosity?
(A) low,low
(B) high,high
(C) low,high
(D) high,low