In ______________ the speed can be varied by changing the position of brushes?

Related Mcqs:

1. Lagging of changes in the magnetization of a substance behind changes in the magnetic field as the magnetic field is varied is known as magnetic_____________?

   A. Retaintivity B. Permeability C. Flux D. Hysteresis...

2. 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...

3. In series motor which of the following methods can be used for changing the flux per pole ?

   A. Tapped field control B. Diverter field control C. Series-parallel control D. Any of the above...

4. The emf induced in a coil by a changing magnetic flux may have unit as______________?

   A. ms-1A B. ms-2A-1 C. kgms2A-1 D. kgm2s-1A-1...

5. The position and velocity errors of a type-2 system are_____________?

   A. constant, constant B. constant, infinity C. zero, constant D. zero, zero...

6. __________________ has relatively wider range of speed control?

   A. Synchronous motor B. Ship ring induction motor C. Squirrel cage induction motor D. D.C. shunt motor...

7. ___________________has least range of speed control?

   A. Slip ring induction motor B. Synchronous motor C. D.C. shunt motor D. Schrage motor...

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

   A. Exhaust fan B. Ceiling fan C. Refrigerator D. Water pump...

9. 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...

10. The travelling speed of cranes varies from_________________?

    A. 20 to 30 m/s B. 10 to 15 m/s C. 5 to 10 m/s D. 1 to 2.5 m/s...