1. The use of the inductor in CSI is to make the source current constant.
A. True
B. False
Answer: A
The inductor in CSI is used to make the source current constant. The input current of CSI should be constant.
2. The output voltage of CSI depends upon the load.
A. True
B. False
Answer: A
The output voltage of CSI depends upon the load. The output current of CSI is fixed as the input source current is fixed.
3. Which one of the elements is used to make R load commutating?
A. Inductor
B. Capacitor
C. Resistor
D. Coil
Answer: B
The capacitor is used to make the R load commutating. It is used in parallel with the resistive load.
4. Calculate the minimum period for ASCI using the data: R=12 kΩ, C=45 μF.
A. 2.58 sec
B. 2.16 sec
C. 2.23 sec
D. 2.48 sec
Answer: B
The minimum time period for ASCI is a
4×R×C
= 4×12×45×.001 = 2.16 sec.
The total time is the sum of charging and discharging time.
5. Full form of ASCI is ___________
A. Auto sequential commutated inverter
B. Auto starter commutated inverter
C. Auto sequential current inverter
D. Auto sequential current inserter
Answer: A
ASCI stands for Auto sequential commutated inverter. No external forced commutation is required for ASCI. The capacitor itself works as a load-commutated inverter.
6. Calculate the maximum frequency for ASCI using the data: R=15 kΩ, C=5 μF.
A. 3.51 Hz
B. 3.69 Hz
C. 3.33 Hz
D. 3.98 Hz
Answer: C
The maximum frequency for ASCI is
1÷(4×R×C) = 1÷(4×15×5×.001) = 3.33 Hz.
The total frequency is the sum of charging and discharging frequency.
7. The output current waveform for R load in CSI is ___________
A. Square
B. Triangular
C. Constant
D. Vertical
Answer: A
The output current of CSI for R load is square in nature. The amplitude of the output current varies from I to -I.
8. T.H.D value for CSI is ________________
A. 48.43 %
B. 41.15 %
C. 39.15 %
D. 46.48 %
Answer: A
T.H.D value for VSI is 48.43 %. Triple harmonics are present in CSI due to which harmonic content increases.
9. What is the distortion factor value in CSI?
A. .85
B. .90
C. .95
D. .88
Answer: B
The distortion value in CSI is .90. The r.m.s value of the fundamental current is 2√2I÷π and the r.m.s value of the output current is I. The distortion factor is (2√2I÷π)÷I = .90.
10. Number of switches turned on in CSI at a single time is __________
A. 2
B. 4
C. 5
D. 3
Answer: A
In CSI two switches conduct at a single time. The common switch used in CSI is thyristor. Thyristors are unidirectional, and bipolar in nature.
