# electric drive( makut exam important questions) mcq -3

Makaut exam odd semester for 4th year Electrical engineering very important questions answers
ELECTRIC DRIVE MCQ TYPE QUESTIONS

1. THE heating time constanat of an electrical machines gives an induction of its
Ans- cooling

2. Intermitted duty rating of an electric motor
Ans- is equal to name plate rating

3. To get the speed higher than the base speed of a dc shunt motar
Ans- field control is used

4. Starting current of a motar is kept low
Ans- to avoid excessive heating

5. If slip value is less than 1, it means the machine is
Ans- Generating

6. The method of interchanging the input supply terminals of the motor is called
Ans-  plugging

7. Calculate the flux produced by the Dc series field winding using the following data , Ia = 5A, Ra=2, Eb=20
Ans- Vt= Eb +IaRa
= 20+5×2
= 30v
8. 20v ,10A, 10rpm separately excited dc motar with armature resistance equal to 0.8 ohms . Calculate back emf developed in the motar when it operates on the full load
Ans- Eb= Vt- I×Ra
= 20 - 10×0.8
= 20 - 8
= 12v

9. Which barking  is not possible in series motar ?
Ans- Regenerative braking

10. The armature of the Dc shunt motar is proportional to
Ans- Armature current only

11. A class 1 contactor should be mechanically servd to withstand
Ans- 0.025 million times

12. Which of the following pair is used for frequency converter
Ans- squarel cage induction motor and wound rotar induction motor

13. In the jaw crushers, a motar has to often start against

14. Which of the following motar is preferred for synthetic fiber mills
Ans- Reluctance motar

15. The Power factor of the reluctance motar at full load is
Ans-. 0.6 to 0.7

Wish you your exam goging very good