DGVCL Exam Paper (11-12-2011)
In the protection of transformers, harmonic restraint is used to guard against

Lightning
Switching over voltages
Magnetizing inrush current
Unbalanced protection

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DGVCL Exam Paper (11-12-2011)
The purpose of skewing of rotor slots in an induction motor is

To reduce the locking tendency of the rotor
To increase the distributuion factor
To reduce the magnetic hum of the motor
To increase the breadth factor

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DGVCL Exam Paper (11-12-2011)
The purpose of interpoles in DC machines is to nullify

The cross-magnetizing effect of armature mmf
The reactance voltage
Both the cross-magnetizing mmf and the reactance voltage
The demagnetizing effect of armature mmf

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DGVCL Exam Paper (11-12-2011)
Due to skin effect

Portion of the conductor near the surface carries more current and the core of the conductor carries less current
Uniform current flows through the conductor
Current flows through the half cross section of the conductor
Portion of the conductor near the surface carries less current and the core of the conductor carries more current

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