Which of the following motors is preferred for boom hoist of a traveling crane?
A. Single phase motor
B. Synchronous motor
C. A.C. slip ring motor
D. Ward-Leonard controlled D.C. shunt motor
Answer: Option C
This Question Belongs to Electrical Engineering >> Industrial Drivers
Rotor of a motor is usually supported on _________ bearings.
A. Ball or roller
B. Needle
C. Bush
D. Thrust
When the load is above _________ a synchronous motor is found to be more economical.
A. 2 kW
B. 20 kW
C. 50 kW
D. 100 kW
For derris and winches which of the following drives can be used?
A. Pole changing squirrel cage motors
B. D.C. motors with Ward-Leonard control
C. A.C. slip ring motors with variable resistance
D. Any of the above
Which of the following motors is preferred for traction work?
A. Universal motor
B. D.C. series motor
C. Synchronous motor
D. Three-phase induction motor
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