Electrical Machines
Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ?

 1, 2 and 3
 2 alone
 1 and 2
 1 and 3

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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

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

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