GATE 2021 CE (CE2) – Question 34
A three-phase signal has critical flow ratios 0.18,0.32,0.22 and lost time 2 s per phase. Find Webster optimum cycle in seconds, nearest integer.
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Correct answer: 48 to 52
Explanation
Total lost time L=6 s and Y=0.72. Webster’s formula is $C_0=(1.5L+5)/(1-Y)=14/0.28=\mathbf{50}$ seconds. Using 2 s as the total instead of the per-phase loss would understate the cycle.