According to Fleming’s left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of_________________?

Related Mcqs:

1. 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

2. The direction of rotation of a D.C. series motor can be changed by___________?

   A. interchanging supply terminals
   B. interchanging field terminals
   C. either of A. and B. above
   D. None of the above

3. In D.C. machines the residual magnetism is of the order of_________________?

   A. 2 to 3 per cent
   B. 10 to 15 per cent
   C. 20 to 25 per cent
   D. 50 to 75 per cent

4. If the field of a D.C. shunt motor gets opened while motor is running______________?

   A. the speed of motor will be reduced %
   B. the armature current will reduce
   C. the motor will attain dangerously high speed 1
   D. the motor will continue to nuvat constant speed

5. 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

6. In a differentially compounded D.C. motor, if shunt field suddenly opens____________?

   A. the motor will first stop and then run in opposite direction as series motor
   B. the motor will work as series motor and run at slow speed in the same direction
   C. the motor will work as series motor and run at high speed in the same direction
   D. the motor will not work and come to stop

7. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens____________?

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

8. If the field winding resistance of a DC shunt motor is increases, its speed will____________?

   If the field winding resistance of a DC shunt motor is increases, its speed will
   A. decreases
   B. increases
   C. remains same
   D. none of the above

9. Which of the following load normally needs starting torque more than the rated torque?

   A. Blowers
   B. Conveyors
   C. Air compressors
   D. Centrifugal pumps

10. Which of the following method of speed control of D.C. machine will offer minimum efficiency ?

    A. Voltage control method
    B. Field control method
    C. Armature control method
    D. All above methods