Compensation Winding MCQs : This section focuses on the "Compensation Winding". These Multiple Choice Questions (MCQs) should be practiced to improve the Compensation Winding skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
Each of the following is valid for interpoles except __________
A. they are connected in parallel with the armature so that they carry part of armature current
B. they are small yoke fixed poles spaced in between main poles
C. their polarity, in case of generator is same as that of main poles ahead
D. they automatically neutralize not only reactance voltage but cross-magnetization also
Question 2
If the critical commutation time is 2 ms but it was observed that the practical commutation took 2.5 ms. This is the case of __________
A. under commutation
B. over commutation
C. critical commutation
D. none of the mentioned
Question 3
If the magnetic circuit of the dc machine is in the saturation region, the armature reaction __________
A. does not affect flux/pole
B. increases the flux/pole
C. decreases flux/pole
D. affects the flux/pole only when armature current is small
Question 4
Mark the most incorrect. In dc generator, commutation can be improved by __________
A. using interpoles
B. using carbon brushes
C. shifting brush axis in direction of armature rotation
D. none of the mentioned
Question 5
The absence of compensating winding lead to __________
A. statically induced emf in armature
B. fluctuations in supply
C. reduction in the flux
D. any of the mentioned
Question 6
The brushes are placed __________
A. along geometrical neutral axis
B. perpendicular to geometrical neutral axis
C. along magnetic neutral axis
D. perpendicular to magnetic neutral axis
Question 7
The brushes should be shifted in _______ direction in generator for the satisfactory operation of commutation.
A. forward
B. reverse to rotation
C. all of the mentioned
D. none of the mentioned
Question 8
The coil under going commutation lies along _____ while the coil getting short circuited lies along ____ for a practical dc machine.
A. gna, mna
B. mna, gna
C. gna, gna
D. mna, mna
Question 9
The commutation process involves basically reversal of current in armature coil as it crosses MNA.
A. True
B. False
Question 10
The compensating winding in dc generator is provided to __________
A. neutralize cross-magnetizing flux
B. neutralize demagnetizing flux
C. neutralize armature mmf
D. maintain magnetizing mmf
Question 11
The principle contributors to magneto motive force is/are __________
A. field current and armature current
B. field excitation
C. electromagnetic torque
D. all of the mentioned
Question 12
The armature reaction is produced mainly by __________
A. load current in armature
B. load current in field
C. all of the mentioned
D. none of the mentioned
Question 13
With no commutating poles used the brushes are given backward lead in the dc motor.
A. True
B. False