A. ball bearings
B. bush bearings
C. magnetic bearmgs
D. needle bearings
Related Mcqs:
- In D.C. generators the pole shoes are fastened to the pole core by_____________?
A. rivets
B. counter sunk screws
C. brazing
D. welding - If a D.C. generator fails to build up the probable cause could not be_____________?
A. imperfect brush contact
B. field resistance less than the critical resistance
C. no residual magnetism in the generator
D. faulty shunt connections tending to reduce the residual magnetism - In D.C. generators, the brushes on commutator remain in contact with conductors which_________________?
A. lie under south pole
B. lie under north pole
C. lie under interpolar region
D. are farthest from the poles - In a D.C. generator the critical resistance refers to the resistance of_____________?
A. brushes
B. field
C. armature
D. load - Magnetic field in a D.C. generator is produced by_______________?
A. electromagnets
B. permanent magnets
C. both A. and B.
D. none of the above - In D.C. generators, lap winding is used for______________?
A. high voltage, high current
B. low voltage, high current
C. high voltage, low current
D. low voltage, low current - For the parallel operation of two or more D.C. compound generators, we should ensure that_______________?
A. voltage of the incoming generator should be same as that of bus bar
B. polarity of incoming generator should be same as that of bus bar
C. all the series fields should be run in parallel by means of equilizer connection
D. series fields of all generators should be either on positive side or negative side of the armature
E. all conditions mentioned above should be satisfied - In D.C. generators on no-load, the air gap flux distribution in space is______________?
A. sinusoidal
B. triangular
C. pulsating
D. flat topped - The purpose of providing dummy coils in a generator is____________?
A. to reduce eddy current losses
B. to enhance flux density
C. to amplify voltage
D. to provide mechanical balance for the rotor - With a D.C. generator which of the following regulation is preferred ?
A. 100% regulation
B. infinite regulation
C. 50% regulation
D. 1% regulation
