A. 0.1 to 0.2 mm
B. 0.2 to 0.3 mm
C. 0.3 to 0.4 mm
D. 0.4 to 0.5 mm
Related Mcqs:
- cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall______________?
A. Direct
B. Indirect
C. Conventional
D. Any of the above - 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. Interpoles
E. All of the above - The weight of copper of both armature and field windings decreases with __________ in number of poles?
A. increase
B. decrease
C. either of the above
D. none of the above - In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made____________?
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 - The noise produced by a ___________ cooled machine is less as the rotor moves in a medium of smaller density?
A. air
B. hydrogen
C. either A. or B.
D. none of the above - The efficiency of a machine should be as ____________ as possible to reduce the operating cost?
A. high
B. low
C. either of the above
D. none of the above - The time taken by the machine to attain 0.632 of its final steady temperature rise is called_____________?
A. heating time constant
B. cooling time constant
C. either A. or B.
D. none of the above - In a D.C. machine the current per brush arm should not be more than_____________?
A. 100 A
B. 200 A
E. 300 A
D. 400 A - In a D.C. machine, the value of peripheral speed should not, normally, exceed___________?
A. 10 m/s
B. 20 m/s
C. 30 m/s
D. 40 m/s - In a D.C. machine the number of brush arms is _________ the number of poles?
A. less than
B. equal to
C. greater than
D. none of the above
