TS ECET EEE 2020-3

1. For a sinusoidal voltage or current, peak factor is

A. RMS Value/Average value
B. Average value/RMS Value
C. Max value/RMS Value
D. RMS Value/Max value

Answer : C. Max value/RMS Value
Explanation:-

2. For the series RLC Circuit shown below, the supply voltage is

A. 500V
B. 200V
C. 100V
D. 400V

Answer : C. 100V
Explanation:-

3. W1 and W2 are the readings of two wattmeters used to measure power of a 3 phase balanced load. The reactive power drawn by the load is

A. W1+W2
B. W1-W2
C. √3(W1+W2)
D. √3(W1-W2)

Answer : D. √3(W1-W2)
Explanation:-

4. Three coils, each having a resistance of 20Ohm and an inductive reactance of 15ohm are connected in a star to a 400v, 3phase,50hz supply. Its power factor is

A. 0.2lag
B. 0.4lag
C. 0.6lag
D. 0.8lag

Answer : D. 0.8lag
Explanation:-

5. In case of an ideal transformer on No-load, the primary supply voltage and current are

A. Inphase with each other
B. Out of phase with each other
C. Mutually perpendicular to each other
D. at ∅° with each other, where 0°<∅°<90°

Answer : C. Mutually perpendicular to each other
Explanation:-

6. A 10 KVA, 2000/400V single phase transformer has R1=5Ohm, X1=12ohm, R2=0.2ohm and X2=0.48ohm. The equivalent resistance of a transformer referred to primary is

A. 26Ohm
B. 5ohm
C. 10ohm
D. 0.4ohm

Answer : C. 10ohm
Explanation:-

7. In a transformer, zero voltage regulation is

A. Not possible
B. possible at unity power factor load
C. possible at leading power factor load
D. possible at lagging power factor load

Answer : C. possible at leading power factor load
Explanation:-

8. what is load at which maximum efficiency occurs in case of a 100kva tranformer with iron loss of 1kw and full load copper loss of 4kw

A. 100 KVA
B. 50 KVA
C. 25.2 KVA
D. 70.7 KVA

Answer : B. 50 KVA
Explanation:-

9. In star-star connection of three phase transformer, if Vl is the line voltage and Il is the line current then phase voltage and phase current is given by

A. VL,IL/√3
B. VL,IL
C. √3VL,IL/√3
D. VL/√3,IL

Answer : D. VL/√3,IL
Explanation:-

10. A 20 KVA, 200/500 V source.what are its voltage ratio and KVA rating respectively

A. 2.5 and 20
B. 3.5 and 20
C. 2.5 and 28
D. 3.5 and 28

Answer : D. 3.5 and 28
Explanation:-