The speed of a D.C. shunt motor can be increased by_______________?

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

If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens__________?

A. nothing will happen to the motor
B. this will make armature to take heavy current, possibly burning it
C. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses D. motor will run at very slow speed

A direct on line starter is used: for starting motors___________?

A. up to 5 H.P
B. up to 10 H.P
C. up to 15 H.P
D. up to 20 H.P

Which of the following motors one will choose to drive the rotary compressor ?

A. D.C. shunt motor
B. D.C. series motor
C. Universal motor
D. Synchronous motor

The speed of a D.C. shunt motor is required to be more than full load speed. This is possible by______________?

A. reducing the field current
B. decreasing the armature current
C. increasing the armature current
D. increasing the excitation current
E. none of the above methods

D.C. series motors are used______________?

A. where load is constant
B. where load changes frequently
C. where constant operating speed is needed
D. in none of the above situations