1. A shearing machine has cyclic load consisting of intermittent light and henry loads. Which of the following D.C. motor will be suitable for this purpose ?

Series motor

Shunt motor

Cumulative compound motor

Differential compound motor

Answer: Cumulative compound motor

Explanation:


2. If a D.C. motor is connected across the A.C. supply it will ?

run at normal speed

not run

run at lower speed

burn due to heat produced in the field winding by eddy currents

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

Explanation:


3. To get the speed of D.C motor below the normal without wastage of electrical energy ...... is used ?

Ward Leonard control

rheostatic control

any of the above method

none of the above method

Answer: Ward Leonard control

Explanation:


4. According to Fleming's left-hand-rule, when the forefinger points in the direction of the field or flux, middle finger wilt point in the direction of ?

current in the conductor

movement of conductor

resultant force on conductor

none of the above

Answer: current in the conductor

Explanation:


5. Which D.C. motor will preferred, for machine tools ?

Series motor

Shunt motor

Cumulative compound motor

Differential compound motor

Answer: Shunt motor

Explanation:


6. For starting a D.C. motor a starter is. required because ?

it limits the speed of the motor

it limits the starting current to a safe value

it starts the rotor

none of the above

Answer: it limits the starting current to a safe value

Explanation:


7. A direct on line starter is used for starting motors ?

up to 5 H.P.

up to 10 H.P.

up to 15 H.P.

up to 20 H.P.

Answer: up to 5 H.P.

Explanation:


8. By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor ?

Frame

Shaft

Commutator

Stator

Answer: Commutator

Explanation:


9. If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking ?

regenerative

plugging

dynamic braking

none of the above

Answer: plugging

Explanation:


10. For which types of D.C. motor, dynamic braking is generally used ?

Shunt motors

Series motors

Compound motors

All of the above

Answer: All of the above

Explanation: