"Electrical drives(Cranes )"

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Electrical drives(Cranes )
1. The consideration involved in the selection of the type of electric drive for a particular application depends on
(A) Speed control range and its nature
(B) Starting torque
(C) Environmental conditions
(D) All of the above.

Get Answer: 
D

2. Which of the following is preferred for automatic drives ?
(A) Synchronous motors
(B) Squirrel cage induction motor
(C) Ward Leonard controlled dc motors
(D) Any of the above.

Get Answer: (Show)
C

3. Which type of drive can be used for hoisting machinery
(A) AC slip ring motor
(B) Ward Leonard controlled DC shunt motor
(C) DC compound motor
(D) Any of the above.

Get Answer: (Hide)
D

4. The motor normally used for crane travel is
(A) AC slip ring motor
(B) Ward Leonard controlled DC shunt motor
(C) Synchronous motor
(D) DC differentially compound motor.

Get Answer: 
A

5. A wound rotor induction motor is preferred over squirrel cage induction motor when the major consideration involved is
(A) high starting torque
(B) low starting current
(C) speed control over limited range
(D) all of the above.

Get Answer: (Hide)
D

6. When smooth and precise speed control over a wide range is desired, the motor preferred is
(A) synchronous motor
(B) squirrel cage induction motor
(C) wound rotor induction motor
(D) dc motor.

Get Answer: 
D

7. When quick speed reversal is a consideration, the motor preferred is
(A) synchronous motor
(B) squirrel cage induction motor
(C) wound rotor induction motor
(D) dc motor.

Get Answer: 

8. Stator voltage control for speed control of induction motors is suitable for
(A) fan and pump drives
(B) drive of a crane
(C) running it as generator
(D) constant load drive.

Get Answer: 
A

9. The selection of control gear for a particular application is based on the consideration of
(A) duty
(B) starting torque
(C) limitations on starting current
(D) all of the above.

Get Answer: 

10. As compared to squirrel cage induction motor, a wound rotor induction motor is preferred when the major consideration is
(A) high starting torque
(B) low windage losses
(C) slow speed operation
(D) all of the above.

Get Answer: 
A

11. A synchronous motor is found to be more economical when the load is above
(A) 1 kW
(B) 10 kW
(C) 20 kW
(D)100kW.

Get Answer: 
D

12. The advantage of a synchronous motor in addition to its constant speed is
(A) high power factor
(B) better efficiency
(C) lower cost
(D) all of the above.

Get Answer: 

13. In motor circuit static frequency changers are used for
(A) power factor improvement
(B) improved cooling
(C) reversal of direction
(D) speed regulation.

Get Answer: 
D

14. In case of traveling cranes, the motor preferred for boom hoist is
(A) AC slip ring motor
(B) Ward Leonard controlled DC shunt motor
(C) Synchronous motor
(D) Single phase motor.

Get Answer: 

15. The characteristics of drive for. crane hoisting and lowering is
(A) smooth movement
(B) precise control
(C) fast speed control
(D) all of the above.

Get Answer: 
D


Posted by Jawed Iqbal at 12:49 AM 
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Monday, April 7, 2014

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