DGVCL Exam Paper (11-12-2011)
The purpose of embedding the damper winding in the pole face of a synchronous motor is to

Eliminate hunting and provide adequate starting torque
Reduce winding losses
Eliminate losses on account of fair friction
Reduce bearing friction

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

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

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

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DGVCL Exam Paper (11-12-2011)
An IDMT relay provides

A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current
A definite time cuttent characteristic
An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current
An inverse time current characteristic

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