51. In order to reduce the hysteresis loss
- core may be laminated
- silicon steel may be used as the core material
- core may be constructed with any permanent magnetic material
- core may be impregnated with varnish
52. Why is the core of the transformer is built up of laminations?
- To reduce eddy current loss
- for convenience of fabrication
- no specific advantage
- for increasing the permeability
53. When are eddy current losses in a transformer reduced?
- if laminations are thick
- if the number of turns in primary winding is reduced
- if the number of turns in secondary winding is reduced
- if laminations are thin
54. Transformer core laminations are coated with an enamel layer in order to
- reduce hum
- attain adhesion between laminations
- insulate laminations from each other
- prevent corrosion of the laminations
55. The degree of mechanical vibrations caused by core laminations in a transformer depends on
- size of laminations
- gauge of laminations
- tightness of clamping
- all of the above
56. The noise, in a transformer, caused by vibrations of laminations set by magnetic forces is termed as
- zoom
- hum
- buzz
- none of these
57. The primary and secondary windings are interlaced for
- easiness of coil making
- reduced leakage reactance
- reduced cost
- uniform heating
58. The concentric windings are used in core type transformers with ______ winding placed next to the core.
- LV
- HV
- primary
- secondary
59. Low voltage windings are placed next to the core in the case of concentric windings as in this case _______ is/are reduced.
- hysteresis and eddy current loss
- leakage fluxes
- copper loss
- insulation requirement
60. When a transformer winding suffers a short circuit, the adjoining turns of the same winding experience
- an attractive force
- a repulsive force
- a pulling force
- no force