In which of the following applications variable speed operation is preferred ?

Related Mcqs:

1. For which of the following applications D.C. motors are still preferred ?

   A. High efficiency operation B. Reversibility C. Variable speed drive D. High starting torque...

2. Which of the following motors is preferred when quick speed reversal is the main consideration ?

   A. Squirrel cage induction motor B. Wound rotor induction motor E. Synchronous motor D. D.C. motor...

3. Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?

   A. D.C. motor B. Squirrel cage induction motor C. Wound rotor induction motor D. Synchronous motor...

4. In which of the following applications the load on motor changes in cyclic order ?

   A. Electric shovels B. Cranes C. Rolling mills D. All of the above...

5. For which of the following applications motor has to start with high acceleration ?

   A. Oil expeller B. Floor mill C. Lifts and hoists D. Centrifugal pump...

6. An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 4×10-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is____________?

   A. 150msec-1 B. 384msec-1 C. 38.4msec-1 D. 200msec-1...

7. RC coupling is generally confined to low power applications because of____________?

   A. Large value of coupling capacitor B. Low efficiency C. Large number of components D. None of the above...

8. For blowers which of the following motor is preferred ?

   A. D.C. series motor B. D.C. shunt motor C. Squirrel cage induction motor D. Wound rotor induction motor...

9. For a motor-generator set which of the following motors will be preferred ?

   A. Synchronous motor B. Slip ring induction motor C. Pole changing induction motor D. Squirrel cage induction motor...

10. Which of the following motors is preferred for boom hoist of a travelling crane ?

    A. Single phase motor B. Synchronous motor C. A.C. slip ring motor D. Ward-Leonard controlled D.C. shunt motor...