Electrical Machine Design MCQ Study - Set 01 - ObjectiveBooks

Electrical Machine Design MCQ Study - Set 01

Practice Test: Question Set - 01

1. Which of the following is an advantage of hydrogen cooling?
    (A) Increase in efficiency
    (B) Increase in ratings
    (C) Increase in life
    (D) All of the above

2. ________ 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

3. _________ electromagnets generally function as holding magnets.
    (A) Tractive
    (B) Portative
    (C) Either of the above
    (D) None of the above

4. Direct water cooling of rotor winding presents
    (A) No mechanical difficulties
    (B) Lesser mechanical difficulties
    (C) Greater mechanical difficulties
    (D) None of the above

5. The winding where dummy coils are used is sometimes called
    (A) Duplex winding
    (B) Triplex winding
    (C) Forced winding
    (D) None of the above

6. The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following?
    (A) Corrugations
    (B) Fins
    (C) Tubes
    (D) All of the above

7. A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils
    (A) 1.5 to 2.5 A/mm2
    (B) 3.5 to 4.5 A/mm2
    (C) 4.0 to 5.0 A/mm2
    (D) 5.4 to 6.2 A/mm2

8. D.C. servomotors are used in
    (A) Purely D.C. control systems
    (B) Purely AC. control systems
    (C) Both D.C. and AC. control systems
    (D) None of the above

9. In a D.C. machine the current per brush arm should not be more than
    (A) 100 A
    (B) 200 A
    (C) 300 A
    (D) 400 A

10. 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) All of the above

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