Electrical Machines
Skewing of the rotor in a 3 - Φ squirrel cage induction motor reduces

  noise, parasitic torque, starting torque and pull out torque.
  noise and parasitic torque, but increase starting and pull-out torque.
  noise, parasitic and starting torque, but increase pull out torque.
  noise and pullout torque, but increase parasitic and starting torque.

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Electrical Machines
Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements,

 1, 2 and 4 are correct
 1, 2 and 3 are correct
 2, 3 and 4 are correct
 1 and 4 are correct

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Electrical Machines
For a single phase capacitor start induction motor which of the following is valid?

 Direction of rotation cannot be changed.
 Rotation can be changed by interchanging supply terminals.
  Rotation can be changed by reversing main winding terminals.
 None of these.

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