D.c. Motors MCQs

Option A: 100%

Option B: around 90%

Option C: anywhere between 75% and 90%

Option D: less than 50%

Correct Answer: less than 50% ✔

Option A: shunt motors

Option B: shunt as well as compound motors

Option C: shunt, compound and series motors

Option D: all D.C. motors

Correct Answer: shunt as well as compound motors ✔

Option A: to improve cooling

Option B: to reduce copper losses

Option C: to increase the generated e.m.f.

Option D: to reduce the sparking

Correct Answer: to reduce the sparking ✔

Option A: Starter for a car

Option B: Drive for a water pump

Option C: Fan motor

Option D: Motor operation in A.C. or D.C

Correct Answer: Starter for a car ✔

Option A: Frame

Option B: Shaft

Option C: Commutator

Option D: Stator

Correct Answer: Commutator ✔

Option A: pumping sets

Option B: air compressors

Option C: electric traction

Option D: machine shops

Correct Answer: electric traction ✔

Option A: almost negligible

Option B: rated full-load current

Option C: less than full-load current

Option D: more than full-load current

Correct Answer: more than full-load current ✔

Option A: back e.m.f. is equal to armature drop

Option B: armature drop is negligible

Option C: flux is proportional to armature current

Option D: flux is practically constant in D:C. shunt motors

Correct Answer: D. flux is practically constant in D:C. shunt motors ✔

Option A: The motor will stop

Option B: The motor will continue to run

Option C: The armature may burn

Option D: The motor will run noisy

Correct Answer: The armature may burn ✔

Option A: up to 5 H.P

Option B: up to 10 H.P

Option C: up to 15 H.P

Option D: up to 20 H.P

Correct Answer: up to 5 H.P ✔

Option A: independent of armature current

Option B: directly proportional to the armature current

Option C: proportional to the square of the current

Option D: inversely proportional to the armature current

Correct Answer: independent of armature current ✔

Option A: decreasing the field current

Option B: increasing the field current

Option C: decreasing the armature current

Option D: increasing the armature current

Correct Answer: decreasing the field current ✔

Option A: more than the normal speed

Option B: loss than the normal speed

Option C: normal speed

Option D: zero

Correct Answer: normal speed ✔

Option A: Ward Leonard control

Option B: rheostatic control

Option C: any of the above method

Option D: none of the above method

Correct Answer: Ward Leonard control ✔

Option A: run at normal speed

Option B: not run

Option C: run at lower speed

Option D: burn due to heat produced in the field winding by .eddy currents

Correct Answer: burn due to heat produced in the field winding by .eddy currents ✔

Option A: shunt motor

Option B: series motor

Option C: differential compoutid D.C. motor

Option D: cumulative compound D.C. motor

Correct Answer: D. cumulative compound D.C. motor ✔

Option A: it limits the speed of the motor

Option B: it limits the starting current to a safe value

Option C: it starts the motor

Option D: none of the above

Correct Answer: it limits the starting current to a safe value ✔

Option A: has its field winding consisting of thick wire and less turns

Option B: has a poor torque

Option C: can be started easily without load

Option D: has almost constant speed

Correct Answer: has its field winding consisting of thick wire and less turns ✔

Option A: the speed will increase abruptly

Option B: the speed will increase in proportion to reduction in load

Option C: the speed will remain almost/constant

Option D: the speed will reduce

Correct Answer: the speed will remain almost/constant ✔

Option A: these motors have high starting torque

Option B: these motors are not self-starting

Option C: back e.m.f. of these motors is zero initially

Option D: to restrict armature current as there is no back e.m.f. while starting

Correct Answer: to restrict armature current as there is no back e.m.f. while starting ✔

Option A: the speed of motor will be reduced %

Option B: the armature current will reduce

Option C: the motor will attain dangerously high speed 1

Option D: the motor will continue to nuvat constant speed

Correct Answer: the motor will attain dangerously high speed 1 ✔

A. current in the conductor aovtaat of conductor
C. resultant force on conductor
D. none of the above

Correct Answer: current in the conductor aovtaat of conductor ✔

Option A: Shunt motor

Option B: Series motor

Option C: Differential compound motor

Option D: Cumulative compound motor

Correct Answer: Cumulative compound motor ✔

Option A: high starting torque

Option B: low starting torque

Option C: variable speed

Option D: frequent on-off cycles

Correct Answer: low starting torque ✔

Option A: Series motor

Option B: Shunt motor

Option C: Cumulative compound motor

Option D: Differential compound motor

Correct Answer: Shunt motor ✔

Option A: Series motor

Option B: Shunt motor

Option C: Differentially compound motor

Option D: Cumulative compound motor

Correct Answer: Series motor ✔

Option A: Lathe machine

Option B: Centrifugal pump

Option C: Locomotive

Option D: Air blower

Correct Answer: Locomotive ✔

Option A: interchanging supply terminals

Option B: interchanging field terminals

Option C: either of A. and B. above

Option D: None of the above

Correct Answer: interchanging field terminals ✔

Option A: Shunt motor

Option B: Series motor

Option C: Cumulative compound motor

Option D: Differentiate compound motor

Correct Answer: Series motor ✔

Option A: 20 nm

Option B: 200 nm

Option C: 250 nm

Option D: 300 nm

Correct Answer: 300 nm ✔

Option A: Prokaryotic organisms

Option B: Unicellular organisms

Option C: Fungi

Option D: Eu-cariotiquic organisms

Correct Answer: Unicellular organisms ✔