Which of the following methods may be adopted to reduce the effects of armature reaction?
A. Increase in length of air gap at pole tips
B. Increasing reluctance of pole tips
C. Compensating windings
D. All of the above
Answer: Option D
D.C. machines designed with a large value of air gap length have
A. worst, ventilation
B. poor ventilation
C. better ventilation
D. none of the above
_________ electromagnets generally function as holding magnets.
A. Tractive
B. Portative
C. Either of the above
D. None of the above
By which of the following methods motor rating for variable load drives can be determined ?
A. Method of average losses
B. Equivalent current method
C. Equivalent torque method
D. Equivalent power method
E. All of the above
In direct cooled system using hydrogen both stator and rotor conductors are made
A. solid
B. hollow
C. perforated
D. any ofthe above
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