Electrical Machines
In a DC machine, for the same value of φ, Z and N; which one of the following statements is correct?

  Armature emf is more with wave winding than with lap winding.
 Armature emf is same as long as the flux density in the air gap remains the same.
 Armature emf is less with wave winding than with lap winding.
 Armature emf depends on weather the machine is running as a motor or generator.

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Electrical Machines
In a step down transformer which one of the following statements is true?

 Secondary current is less than primary current.
  Number of secondary turns is less than primary turns.
 Secondary power is less than primary power.
 Number of secondary turns is more than that of primary.

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

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