Electrical Machine Design

A. Mild steel
B. Copper
C. Aluminium
D. Cast-iron

A. Metal graphite brushes
B. Hard carbon brushes
C. Electro-graphitic brushes
D. Natural graphite brushes

A. Increased I R losses
B. Increased core losses
C. Poor commutation
D. Change in motor parameters
E. All of the above

A. less than
B. equal to
C. greater than
D. none of the above

A. worst, ventilation
B. poor ventilation
C. better ventilation
D. none of the above

A. between 5 to 10 mm
B. between 10 to 15 mm
C. between 15 to 20 mm
D. between 25 to 35 mm

A. quiet
B. noisy
C. either of the above
D. none of the above

A. equal to that of armature mmf
B. less in comparison with the armature mmf
C. large in comparison with the armature mmf
D. none of the above

A. 10 m/s
B. 20 m/s
C. 30 m/s
D. 40 m/s

A. increase
B. decrease
C. either of the above
D. none of the above