A. Frequency of magnetic reversals
B. Maximum value of flux density
C. Volume and grade of iron
D. Rate of flow of ventilating air
Related Mcqs:
- Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?
A. Providing laminations in armature core
B. Providing laminations in stator
C. Using non-magnetic material for frame
D. Using material of low hysteresis co-efficient for armature core material - Which D.C. motor will be preferred for machine tools ?
A. Series motor
B. Shunt motor
C. Cumulative compound motor
D. Differential compound motor - Which one of the following is not the function of pole shoes in a D.C. machine ?
A. To reduce eddy current loss
B. To support the field coils
C. To spread out flux for better uniformity
D. To reduce the reluctance of the magnetic path - Which of the following method of speed control of D.C. machine will offer minimum efficiency ?
A. Voltage control method
B. Field control method
C. Armature control method
D. All above methods - The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?
A. hysteresis loss
B. field copper loss
C. armature copper loss
D. eddy current loss - Which of the following loss in a D.C. generator varies significantly with the load current ?
A. Field copper loss
B. Windage loss
C. Armature copper loss
D. None of the above - Which of the following loss in a D.C. generator is dissipated in the form of heat?
A. Mechanical loss
B. Core loss
C. Copper loss
D. All of the above - The ratio of starting torque to full-load torque is least in case of____________?
A. series motors
B. shunt motors
C. compound motors
D. none of the above - Torque developed by a D.C. motor depends upon_____________?
A. magnetic field
B. active length of the conductor
C. current flow through the conductors
D. number of conductors
E. radius of armature
F. all above factors - The size of poxvirus is_______________?
A. 20 nm
B. 200 nm
C. 250 nm
D. 300 nm
