A Best Way To Crack Gorenment Job Exams

Electrical Engineering Objective Questions { DC Motors }

22.  Each commutator segment is connected to the armature conductor by means of
A. insulator
B. copper lug
C. resistance wire
D. carbon brush

23.  In a dc generator, sparking between brushes and commutator surface may be due to
A. overcommutation
B. undercommutation
C. to rapid reversal of current
D. any of the above

24.  Brushes for commutators for 220 V dc generator are generally made of
A. copper
B. carbon copper
C. electrographite
D. graphited copper

25.  Commutato r of a dc machine acts as a
A. fullwave recter
B. halfwave rectifier
C. inverter
D. controlled rectifier

26.  The maximum nuber of brushes which machine may be used in an electrical machine isnumber of poles i the machine equal to
D. either (a) or (b) above

27.  For a lapature with Z conductors and P poles, the maximum number of equalizer rings required are
A. P

28.  If in is the degree of multiplicity and p is the number of poles, the number of parallel paths in a wave winding will be
B. 2m
C. mp
D. 2 rap

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