Which of the following loss in a D.C. generator varies significantly with the load current ?

Related Mcqs:

1. 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

2. Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?

   A. Hysteresis losses
   B. Eddy current losses
   C. Copper losses
   D. Windage losses

3. 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

4. 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

5. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is______________?

   A. 2.36%
   B. 4.76%
   C. 6.77%
   D. 8.84%

6. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this______________?

   A. series motor
   B. shunt motor
   C. compound motor
   D. any of the above

7. In a D.C. generator all of the following could be the effects of iron losses except___________?

   A. Loss of efficiency
   B. Excessive heating of core
   C. Increase in terminal voltage
   D. Rise in temperature of ventilating air

8. The total losses in a well designed D.C. generator of 10 kW will be nearly______________?

   A. 100 W
   B. 500 W
   C. 1000 W
   D. 1500 W

9. The condition for maximum efficiency for a D.C. generator is______________?

   A. eddy current losses = stray losses
   B. hysteresis losses = eddy current losses
   C. copper losses = 0
   D. variable losses = constant losses

10. In a D.C. generator, the iron losses mainly take place in___________/

    A. yoke
    B. commutator
    C. armature conductors
    D. armature rotor