ECET EEE Model Paper-1 Part4

 

1. If the speed of a D.C. shunt motor is increased the back emf of the motor will

A. Decrease
B. Increase
C. Remain same
D. Becomes zero

Answer : Increase
Explanation:-

2. In lap winding the number of brushes is always

A. Double the number of poles
B. Same as the number of poles
C. Half of the number of poles
D. Two

Answer : Same as the number of poles
Explanation:-

3. The purpose of providing dummy cols in a D.C. generator is

A. To enhance flux density
B. To amplify voltage
C. To provide mechanical balance for the rotor
D. To reduce eddy current

Answer : To provide mechanical balance for the rotor
Explanation:-

4. Resistance can be measured with the help of

A. Watt meters
B. Voltmeters
C. Ammeters
D. Ohm meters and resistance bridges

Answer : Ohm meters and resistance bridges
Explanation:-

5. Compensating windings are used in D.C. generators

A. Mainly to reduce the eddy currents
B. To provide path for the circulation of cooling air
C. To neutralize the cross-magnetizing effect of the armature reaction
D. None of the above

Answer : To neutralize the cross-magnetizing effect of the armature reaction
Explanation:-

6. No-load speed of the which of the following motor will be highest

A. Shunt motor
B. Series motor
C. Cumulative compound motor
D. Differential compound motor

Answer : Series motor
Explanation:-

7. In a portable instrument, the controlling torque is provided by

A. Spring
B. Gravity
C. Eddy currents
D. All of the above

Answer : Spring
Explanation:-

8. Small D.C. motors upto 5 H.P. usually have

A. 2 poles
B. 4 poles
C. 8 poles
D. 6 poles

Answer : 2 poles
Explanation:-

9. A 220 V D.C. generator is running at full speed without any excitation the open circuit voltage will be

A. Zero
B. About 2 V
C. About 50 V
D. 220 V

Answer : About 2 V
Explanation:-

10.The period of sine wave is 1/50 seconds .its frequency is

A. 20 Hz
B. 30 Hz
C. 50 Hz
D. 500 Hz

Answer : 50 Hz
Explanation:-