A. high
B. low
C. either of the above
D. none of the above
Related Mcqs:
- 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 heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ?
A. Conduction
B. Convection
C. Radiation
D. All 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 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 - The operation of a D.C. machine with large air gap lengths is comparatively_____________?
A. quiet
B. noisy
C. either of the above
D. none of the above - 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 - The stator of a D.C. machine comprises of_____________?
A. main poles
B. interpoles
C. frame
D. all of the above - The laminations of the armature of a D.C. machine are usually ___________ thick?
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
