91. Which type of winding is used in 3phase shell-type transformer ?
(a) Circular type
(b) Sandwich type
(c) Cylindrical type
(d) Rectangular type
Ans: b
92. 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
Ans: a
93. Open circuit test on transformers is conducted to determine
(a) hysteresis losses
(b) copper losses
(c) core losses
(d) eddy current losses
Ans: c
94. Short circuit test on transformers is conducted to determine
(a) hysteresis losses
(b) copper losses
(c) core losses
(d) eddy current losses
Ans: b
95. For the parallel operation of single phase transformers it is necessary that they should have
(a) same efficiency
(b) same polarity
(c) same kVA rating
(d) same number of turns on the secondary side.
Ans: b
96. The transformer oil should have _____ volatility and _____ viscosity.
(a) low,low
(b) high,high
(c) low,high
(d) high,low
Ans: a
97. The function of breather in a transformer is
(a) to provide oxygen inside the tank
(b) to cool the coils during reduced load
(c) to cool the transformer oil
(d) to arrest flow of moisture when outside air enters the transformer
Ans: d
98. The secondary winding of which of the following transformers is always kept closed ?
(a) Step-up transformer
(b) Step-down transformer
(c) Potential transformer
(d) Current transformer
Ans: d
99. The size of a transformer core will depend on
(a) frequency
(b) area of the core
(c) flux density of the core material
(d) (a) and (b) both
Ans: d
100. N atural air coo ling is generally restricted for transformers up to
(a) 1.5 MVA
(b) 5 MVA
(c) 15 MVA
(d) 50 MVA
Ans: a
(a) Circular type
(b) Sandwich type
(c) Cylindrical type
(d) Rectangular type
Ans: b
92. 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
Ans: a
93. Open circuit test on transformers is conducted to determine
(a) hysteresis losses
(b) copper losses
(c) core losses
(d) eddy current losses
Ans: c
94. Short circuit test on transformers is conducted to determine
(a) hysteresis losses
(b) copper losses
(c) core losses
(d) eddy current losses
Ans: b
95. For the parallel operation of single phase transformers it is necessary that they should have
(a) same efficiency
(b) same polarity
(c) same kVA rating
(d) same number of turns on the secondary side.
Ans: b
96. The transformer oil should have _____ volatility and _____ viscosity.
(a) low,low
(b) high,high
(c) low,high
(d) high,low
Ans: a
97. The function of breather in a transformer is
(a) to provide oxygen inside the tank
(b) to cool the coils during reduced load
(c) to cool the transformer oil
(d) to arrest flow of moisture when outside air enters the transformer
Ans: d
98. The secondary winding of which of the following transformers is always kept closed ?
(a) Step-up transformer
(b) Step-down transformer
(c) Potential transformer
(d) Current transformer
Ans: d
99. The size of a transformer core will depend on
(a) frequency
(b) area of the core
(c) flux density of the core material
(d) (a) and (b) both
Ans: d
100. N atural air coo ling is generally restricted for transformers up to
(a) 1.5 MVA
(b) 5 MVA
(c) 15 MVA
(d) 50 MVA
Ans: a
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