Electrical Machines
Flashing of DC generator means

  creation of residual magnetism by a DC source.
  increasing flux density by providing extra ampere-turns in field.
None of these
 neutralization of residual magnetism.

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Electrical Machines
The following statements relate to compensating winding (CW) and interpole winding (IW) of a dc machine : 1. CW neutralizes the armature reaction under a pole pitch 2. IW is connected in series with armature circuit 3. IW produces mmf in the commutating zone only 4. CWmmf is directed along the brush axis 5. Mmf produced by IW is equal to armature mmf From these, the correct statements are

 2, 3, 4
 1, 2, 3, 4 and 5
 2, 3, 4, 5
 1, 3, 4, 5

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Electrical Machines
In an alternator, voltage drops occurs in

  armature resistance only.
  armature resistance and leakage reactance.
  armature resistance, leakage reactance, armature reaction and earth connection.
  armature resistance, leakage reactance and armature reaction.

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Electrical Machines
Consider the following statements : Interpoles in dc machines 1. reducearmature reaction effects in the interpolar region 2. have the same dimension as main polls 3. have their windings connected in series with the armature 4. have same number of turns as the armature 5. have the polarity same as that of the main pole ahead in a motor From these, the correct statements are

 1, 3 and 5
 1, 2 and 3
 1, 2, 3 and 5
 1 and 3

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