Electrical Machine MCQs for test preparation. Includes multiple-choice questions and answers on electrical machines, providing a comprehensive resource for students and professionals.
Which of the following adds to the pitch of the commutator ?
A. Number of commutator segments between two successive coils
B. The distance between the staring of first coil and its next successive coil
C. Number of conductors spanned by one coil at the back end of the armature
D. Number of conductors spanned by one coil at the front end of the armatureFour pole lap winding is used in DC machines. How many parallel routes are there ?
A. 2
B. 3
C. 4
D. 6Windings on DC machines are ____ ?
A. short pitched
B. full pitched
C. either of these
D. None of themWhich of the following windings is required for every DC machine ?
A. open type winding
B. closed winding
C. lap winding
D. wave windingWhich of the following bearings are suitable for the reason ?
A. roller bearings → large machines
B. ball bearings → small machines
C. neither 1 nor 2
D. Both a and bWhich of the following brush types and how they should be used is/are right:
A. copper graphite → low voltage high current density
B. carbon brush → normal ratings
C. electro graphite → large ratings
D. All of themIn DC generators brushes are used for _____ ?
A. reduce eddy current loss
B. convert ac armature current in to dc
C. collecting of current without any sparkings
D. collecting of voltageA DC machine uses seventy-two coils. Determine the necessary number of commutator segments.
A. 13
B. 45
C. 36
D. 72In DC machine yoke offers ___ ?
A. flux path completion
B. mechanical protection to the machine
C. produce working flux
D. Both A and BA DC generator without commutator is a ____ ?
A. DC generator
B. induction motor
C. DC motor
D. AC generator