161. Calculate the r.m.s value of the output current having an amplitude of 2 A for CSI.
A. 3 A
B. 4 A
C. 2 A
D. 1 A
Answer: B
The r.m.s value of the output current having an amplitude of 2 A for CSI is 2A. The waveform for output current is a square wave. The r.m.s value of the square wave is its amplitude.
162. Calculate the r.m.s value of the fundamental component of the output current having an amplitude of 3 A for CSI.
A. 2.80 A
B. 2.70 A
C. 2.54 A
D. 3.48 A
Answer: B
The r.m.s value of the fundamental component of the output current is
2√2I÷π = 8.48÷3.14 = 2.70 A. The r.m.s value of the output current is I.
163. Calculate the string efficiency if the de-rating factor is .76.
A. 24 %
B. 25 %
C. 26 %
D. 27 %
Answer: A
The string efficiency is calculated for the series and parallel connection of SCRs. The value of string efficiency is 1-(De-rating factor) = 1-.76 = 24 %.
164. 20 V rated 8 SCRs are connected in series. The operation voltage of the string is 50. Calculate the De-rating factor.
A. .67
B. .68
C. .69
D. .70
Answer: B
The string efficiency can be calculated using the formula
operation voltage÷(Number of SCRs×Rated voltage) =
50÷(20×8) = .31.
The De-rating factor value is 1-.31 = .68.
165. Forced commutated CSI require _________
A. Diode
B. Resistor
C. Inductor
D. Capacitor
Answer: D
Forced commutated CSI requires a capacitor. The capacitor acts as a commutating element. It is connected in parallel with the load.
