Electrical Machines
A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is

 36.36% increase
 36.36% increase
 18.18% increase
 36.36% decrease

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Electrical Machines
In a loaded DC generator, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will

 improve with fall of terminal voltage.
 deteriorate with fall of terminal voltage.
 deteriorate with rise in terminal voltage.
 improve with rise in terminal voltage.

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Electrical Machines
In a DC machine

 emf in armature conductors and at the terminals is alternating.
 current and emf at the terminals are alternating.
 current and emf in armature are alternating.
 current and emf in armature are unidirectional

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