DC MOTOR MCQS SET 04

DC MOTOR MCQS SET 04

1. Which D.C. motor has got maximum self loading property?
(a) Series motor
(b) Shunt motor
(c) Cumulatively compounded 'motor
(d) Differentially compounded motor 

Ans:  d

2. In D.C. motor which of the following can sustain the maximum temperature rise?
(a) Slip rings
(b) Commutator
(c) Field winding
(d) Armature winding 

Ans:  c

3. Which of the following law/rule can he used to determine the direction of rotation of
D.C. motor ?
(a) Lenz's law
(b) Faraday's law
(c) Coloumb's law
(d) Fleming's left-hand rule 

Ans:  d
 
4. Which of the following load normally needs starting torque more than the rated torque?
(a) Blowers
(b) Conveyors
(c) Air compressors
(d) Centrifugal pumps 

Ans:  b

5. The starting resistance of a D.C. motor is generally
(a) low
(b) around 500 Q
(c) 1000 Q
(d) infinitely large 

Ans:  a

6. The speed of a D.C. series motor is
(a) proportional to the armature current
(b) proportional to the square of the armature current
(c) proportional to field current
(d) inversely proportional to the armature current 

Ans:  d

7. In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to
(a) 100% of the previous value
(b) 50% of the previous value
(c) 25% of the previous value
(d) 10% of the previous value
(e) none of the above 

Ans:  c

8. The current drawn by the armature of D.C. motor is directly proportional to
(a) the torque required
(b) the speed of the motor
(c) the voltage across the terminals
(d) none of the above 

Ans:  a

9. The power mentioned on the name plate of an electric motor indicates
(a) the power drawn in kW
(b) the power drawn in kVA
(c) the gross power
(d) the output power available at the shaft 

Ans:  d