D.C. Machines

91. The torque-speed characteristics of an A.C. operated universal motor has a _________ characteristic and it _________ be started under no-load condition.

1. inverse, can
2. nearly inverse, can
3. inverse, cannot
4. nearly inverse, cannot

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92. The two windings of a transformer is

1. conductively linked.
2. inductively linked.
3. not linked at all.
4. electrically linked.

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93. The usual test to find the efficiency of the traction motor is

1. Field's test
2. Retardation test
3. Hopkinson's test
4. Swinburn's test

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94. Voltage equation of a dc motor is

1. V = Eb + IaRa
2. Eb = V + IaRa
3. V = Eb/IaRa
4. V = Eb + Ia2Ra

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95. When a synchronous motor is running at synchronous speed, the damper winding produces

1. damping torque.
2. eddy current torque.
3. torque aiding the developed torque.
4. no torque.

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96. When load is removed, motor will run at the highest speed.

1. Shunt
2. Cumulative – compound
3. Differential compound
4. Series

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97. Which generator has poorest voltage regulation

1. series
2. shunt
3. compound
4. high

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98. which of the following motor has the constant speed?

1. Series motor
2. Shunt motor
3. Cumulatively compound motor
4. All of the above

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