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MCQ of D.C motor page-1MCQ of D.C motor page-2MCQ of D.C motor page-3MCQ of D.C motor page-4Multiple Choice Question (MCQ) of D.C. Machines page-1Multiple Choice Question (MCQ) of D.C. Machines page-2Multiple Choice Question (MCQ) of D.C. Machines page-3Multiple Choice Question (MCQ) of D.C. Machines page-4Multiple Choice Question (MCQ) of D.C. Machines page-5Multiple Choice Question (MCQ) of D.C. Machines page-6Multiple Choice Question (MCQ) of D.C. Machines page-7Multiple Choice Question (MCQ) of D.C. Machines page-8Multiple Choice Question (MCQ) of D.C. Machines page-9Multiple Choice Question (MCQ) of D.C. Machines page-10MCQ of D.C motor page-5MCQ of D.C motor page-6MCQ of D.C motor page-7MCQ of D.C motor page-8MCQ of D.C motor page-9MCQ of D.C motor page-10MCQ of D.C motor page-11MCQ of D.C motor page-12MCQ of D.C motor page-13MCQ of D.C motor page-14MCQ of D.C motor page-15MCQ of D.C motor page-16MCQ of D.C motor page-17MCQ of D.C motor page-18

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-Power

MCQ of D.C motor page-16


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111. A 220 V series motor in which the total armature and field resistance is 0.1 Ω is working with unsaturated field, taking 100 A and running at 800 rpm. The torque develops will be

A) 400 Nm
B) 300 Nm
C) 250 Nm
D) 200 Nm.

Ans : (C)

112. For maximum efficiency of dc motor

A) variable loss = constant loss
B) variable loss should be half of the constant loss
C) constant loss should be half of the variable loss
D) none of these.

Ans : (A)

113. The amount of flux leakage will depend on the

A) shape of magnet core
B) length of airgap
C) flux density employed in core and teeth
D) all of the above.

Ans : (D)

114. The usual value of flux leakage coefficient is

A) 0.5 to 0.6
B) 1.0
C) 1.1 to 1.3
D) 2 to 2.2.

Ans : (C)

115. If starter is not used with large dc motor for starting, it will draw a starting current which

A) Is many times its rated full load current
B) Will produce excessive voltage drop in line
C) May damage the armature and commutator
D) All of the above.

Ans : (D)

116. A dc series motor is running with a diverter connected across its field winding. If the diverter resistance is reduced then the speed of the motor will

A) increase
B) decrease
C) become excessively high
D) remain unaltered.

Ans : (A)

117. Variation in speed by Ward Leonard control of dc motors occurs due to variation in

A) supply voltage
B) armature voltage
C) armature current
D) field excitation.

Ans : (B)

118. The variable resistor connected across the series field of a dc series motor is called the

A) field divider
B) voltage divider
C) potential divider
D) none of these.

Ans : (A)

119. If the no-voltage release in a dc motor starter fails to operate on failure of supply, on resumption of supply the motor will

A) not start automatically
B) start automatically without trouble
C) develop very low starting torque
D) get damaged due to flow of excessive current in the armature.

Ans : (D)

120. If the resistance is connected across the armature of a dc series motor, its speed for a constant load torque will

A) increase
B) decrease
C) remain unaltered
D) become zero.

Ans : (B)


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