A. 200 to 400 r.p.m
B. 600 to 1000 r.p.m
C. 1000 to 1500 r.p.m
D. 2000 to 2500 r.p.m
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 - The design of mechanical parts is particularly important in case of __________ speed machines?
A. low
B. medium
C. high
D. any of the above - 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 - Electrical machines having power outputs ranging from a few kW up to approximately 250 kW may be classified as_____________?
A. small size machines
B. medium size machines
C. large size machines
D. any of the above - Electrical machines having a power output up to about 750 W may be called__________machines?
A. small size
B. medium size
C. large size
D. any of the above - _______________is universally used for windings of electrical machines because it is easily workable without any possibility of fracture?
A. Silver
B. Steel
C. Aluminium
D. Copper - Machines cooled by direct cooling method may be called_____________?
A. “supercharged”
B. “inner cooled”
C. “conductor cooled”
D. any of the above - In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made____________?
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 - D.C. machines designed with a large value of air gap length have_____________?
A. worst, ventilation
B. poor ventilation
C. better ventilation
D. none of the above
