Index

SymbolsTransformerRelayPower-SystemBasic-electricalACSR-ConductorCircuit-BreakerInterview-questions-of-Basic-ElectricityInterview-questions-of-transformerInsulatorCurrent-TransformerMCQMCQ-powersystemThermal-power-stationInterview-questions-of-Power-SystemPower-ElectronicsInterview-questions-of-Underground-CableInterview-questions-of-IlluminationIlluminationMCQ-of-ElectronicsMCQ-of-Basic-ElectricalMCQ-of-Transformers MCQ-of-D.C-motor MCQ-of-D.C-generatorsMCQ-Control-SystemMCQ-Measurementsmcq-of-Generation-power-systemMCQ-of-Induction-MotorMCQ-of-Transmission-DistributionMCQ-of-Electrical-MachinesMCQ-of-Alternator-and-Synchronous-MotorsMCQ-Electric-PowerMCQ-Illumination

MCQ of Transformer page-23


≪ Previous Next ≫

121. A transformer will have highest efficiency near

A) 25% of rated load
B) 50% of rated load
C) 75% of rated load
D) 93% of rated load.

Ans : (D)

122. A transformer working under the conditions of maximum efficiency has total losses of 1600 W. While operating at half load, the copper loss will be

A) 100 W
B) 200 W
C) 400 W
D) 800 W.

Ans : (B)

123. Operating time of Buchholz relay is of the order of

A) 0.1 micro second
B) 0.1 milli second
C) 0.1 second
D) 1 second.

Ans : (B)

124. A Buchholz relay will operate in a transformer whenever there is

A) large internal fault
B) saturation of magnetic circuit
C) over load
D) any of the above.

Ans : (A)

125. The following is the apparent disadvantage of autotransformer as compared to two-winding transformer.

A) Power rating is greater
B) Efficiency is low
C) Conductive isolation is not present
D) Voltage regulation is low.

Ans : (C)

126. The colour of moist silica gel is

A) yellow
B) blue
C) brown
D) red.

Ans : (D)

127. In a 50 kVA transformer, the number of turns in the primary and secondary winding are 834 and 58 respectively. If the primary is connected to 3300 V supply the secondary current will be

A) 15 A
B) 30 A
C) 218 A
D) 438 A.

Ans : (C)

128. The essential condition for parallel operating of two single-phase transformers is that they should have same

A) polarity
B) voltage ratio
C) capacity
D) efficiency.

Ans : (B)

129. A transformer has an efficiency of 85% and works at 100 V, 4 KVA. If the secondary voltage is 200 V, find the primary current.

A) 40 A
B) 30 A
C) 20 A
D) 10 A.

Ans : (A)

130. An auto transformer has

A) only one winding
B) two winding of the same gauge of wire
C) two winding of different materials
D) more than two windings.

Ans : (A)


≪ Previous Next ≫


Related topics :