AP ECET EEE 2018-4

1. An auto transformer supplies a load of 3KW at 115 V at unity power factor. If the applied primary voltage is 230v, calculate the power transferred to the load inductively by neglecting losses

A. 0.5Kw
B. 1KW
C. 1.5KW
D. 2KW

Answer : C. 1.5KW
Explanation:-

2. The frequency of a 4-pole alternator running at 1500 rpm will be _______

A. 100 HZ
B. 60 HZ
C. 50 HZ
D. 25 HZ

Answer : C. 50 HZ
Explanation:-

3. The dark and bright lamp methos is used for

A. Transfer of load
B. synchronizing
C. Balancing of load
D. Phase sequence

Answer : B. synchronizing
Explanation:-

4. In an alternator, the armature reaction influences _______

A. generated voltage per phase
B. frequency
C. operating speed
D. winding losses

Answer : D. winding losses
Explanation:-

5. The power developed by a synchronous motor will be maximum when the load angle is _______

A. 0 degrees
B. 45 degrees
C. 60 degrees
D. 90 degrees

Answer : D. 90 degrees
Explanation:-

6. An overexited synchronous motor is used for _____

A. fluctuating loads
B. variable speed loads
C. low torque loads
D. power factor corrections

Answer : D. power factor corrections
Explanation:-

7. If the field of a synchronous motor is under excited, the power factor will be ______

A. zero
B. unity
C. lagging
D. leading

Answer : C. lagging
Explanation:-

8. A 4-pole.3-phase induction motor is running at 4% slip at full load. If the speed of the motor is 720 rpm, the supply frequency is

A. 15 Hz
B. 25 Hz
C. 50 Hz
D. 60 Hz

Answer : B. 25 Hz
Explanation:-

9. The rotor power output of a 3-phase induction motor is 15Kw and the correponding slip is 4%. The rotor copper loss will be

A. 600 W
B. 625 W
C. 650 W
D. 700 W

Answer : B. 625 W
Explanation:-

10. When the rotor of a 3-phase induction motor is blocked, the slip is _____

A. 1
B. 0.5
C. 0.1
D. 0

Answer : A. 1
Explanation:-