D.C. Motors

Ward Leonard method of speed control is basically a______________?

A. field control method
B. armature controlled method
C. field diverter
D. frequency control method

Which of the following test can be performed on DC series motor?

A. Swinburne test
B. Hopkinson test
C. Brake test
D. Field test

Armature reaction in dc motor results___________?

A. decrease in speed
B. increase in speed
C. short circuit
D. open circuit

In a DC motor the inter-pole winding is connected in________________?

A. series with field winding
B. series speed armature winding
C. parallel big field winding
D. parallel with armature winding

A dc series motor should not be started on no load because it would___________?

A. not develop starting torque
B. fail to start without load
C. run at dangerously high speed
D. draw more current without producing sufficient torque

Which of the following method is used for the speed control of DC shunt motor?

A. voltage control method
B. flux control method
C. rheostat control method
D. all of the above

With the increase in temperature, the speed of DC series motor______________?

A. decreases
B. increases
C. remain same
D. none of the above

With the increase in temperature, the speed of DC shunt motor____________?

A. decreases.
B. increases
C. remain same
D. none of the above

In which of the following device the generated emf and armature current are in the opposite directions?

A. dc generator
B. dc motor
C. transformer
D. all of the above

If the load on a DC shunt motor is increases, its speed is slightly reduced due to______________?

A. increase in armature current
B. increase in flux
C. decrease in reactance
D. decrease in back emf