A. equal to that of armature mmf
B. less in comparison with the armature mmf
C. large in comparison with the armature mmf
D. none of the above
Related Mcqs:
- In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?
A. increase
B. decrease
C. either of the above
D. none of the above - In direct cooled system using hydrogen both stator and rotor conductors are made____________?
A. solid
B. hollow
C. perforated
D. any ofthe above - cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall______________?
A. Direct
B. Indirect
C. Conventional
D. Any of the above - The weight of copper of both armature and field windings decreases with __________ in number of poles?
A. increase
B. decrease
C. either of the above
D. none of the above - 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 - ___________ brushes are fragile and cause excessive wear of commutator?
A. Natural graphite
B. Hard carbon
C. Electro graphitic
D. Metal graphite - 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 - In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?
A. small
B. medium
C. large
D. any of the above. - The action of electromagnetic machines can be related to which of the following basic principles __________?
A. Induction
B. Interaction
C. Alignment
D. All of the above - Multiple inlet system of air cooling of turbo-alternators can be used for machines of rating upto_______________?
A. 10 MW
B. 30 MW
C. 60 MW
D. 150 MW
