D.C. Motors

101. Which D.C. motor will be suitable along with flywheel for intermittent light and heavy loads?

1. Series motor
2. Shunt motor
3. Cumulatively compounded motor
4. Differentially compounded motor

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102. Which method of braking is generally used in elevators?

1. Plugging
2. Regenerative braking
3. Rheostatic braking
4. None of the above

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103. Which motor has the poorest speed control?

1. Differentially compounded motor
2. Cumulatively compounded motor
3. Shunt motor
4. Series motor

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104. Which motor should not be started on no-load?

1. Series motor
2. Shunt motor
3. Cumulatively compounded motor
4. Differentially compounded motor.

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105. Which of the following application requires high starting torque?

1. Lathe machine
2. Centrifugal pump
3. Locomotive
4. Air blower

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106. Which of the following law/rule can he used to determine the direction of rotation of D.C. motor?

1. Lenz's law
2. Faraday's law
3. Coloumb's law
4. Fleming's left-hand rule

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107. Which of the following load normally needs starting torque more than the rated torque?

1. Blowers
2. Conveyors
3. Air compressors
4. Centrifugal pumps

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108. Which of the following loss in a D.C. generator is dissipated in the form of heat?

1. Mechanical loss
2. Core loss
3. Copper loss
4. All of the above

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109. Which of the following loss in a D.C. generator varies significantly with the load current?

1. Field copper loss
2. Windage loss
3. Armature copper loss
4. None of the above

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110. Which of the following losses are significantly reduced by laminating the core of a D.C. generator?

1. Hysteresis losses
2. Eddy current losses
3. Copper losses
4. Windage losses

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