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

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Electrical Machines
In speed control of DC Series motor, speed lower than the rated speed can be obtained by

 Connecting an additional resistance in the field circuit.
 Any of the above.
 Connecting an additional resistance in stator circuit.
 Connecting an additional resistance in the armature circuit.

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Electrical Machines
In a dc generator operating on load with its brushes on the geometrical neutral axis (GNA), the magnetic neutral axis (MNA) is shifted in the direction of rotation. Now, if the brushes are given a lead of 90° (electrical), then the MNA will

 coincide with the GNA
 shift forward by more than 90°
 shift forward by less than 90°
 shift forward by 90°

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