DGVCL Exam Paper (11-12-2011)
DC series motors are best suited for traction work because

Its torque is proportional to the square of the armature current and speed is inversely proportional to torque
Its torque is proportional to the square of the armature current and speed is directional proporational to torque
Torque and speed are inversely proportional to the square of the armature current
Torque and speed are proportional to the square of the armature current

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DGVCL Exam Paper (11-12-2011)
The advantage of slipring induction motor over the squirrel cage induction motor is

It has a higher efficiency
It can be started with the help of rotor resistances
It's power factor is higher
It is suitable for higher speeds

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DGVCL Exam Paper (11-12-2011)
Which of the following correctly represents the sequence of operations of isolator, circiut breaker and earthing switch while opening a circuit?

Close circuit breaker-close isolator - open earthing switch
Open isolator close circuit breaker-open earthing switch
Open circuit breaker-open isolator-close earthing switch
Close earthing switch - open ciruit- breaker-open islotor

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