A. Mild steel
B. Copper
C. Aluminium
D. Cast-iron
is usually used for brush rockers____________? Read More »
Electrical Machine Design A. Metal graphite brushes
B. Hard carbon brushes
C. Electro-graphitic brushes
D. Natural graphite brushes
Which of the following brushes can be used for high values of current density ? Read More »
Electrical Machine Design 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
In a D.C. machine the number of brush arms is _________ the number of poles? Read More »
Electrical Machine Design A. worst, ventilation
B. poor ventilation
C. better ventilation
D. none of the above
D.C. machines designed with a large value of air gap length have_____________? Read More »
Electrical Machine Design A. between 5 to 10 mm
B. between 10 to 15 mm
C. between 15 to 20 mm
D. between 25 to 35 mm
In D.C. machines the usual limit of slot pitch is________________? Read More »
Electrical Machine Design 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
