Previous Year Question
For a symmetrical delta connection where R1=R2=R3=R, what is the equivalent resistance Req when converted to a star (Y) network?
Correct answer: B
Explanation
For delta-to-star conversion, each star resistance equals the product of the two adjacent delta resistances divided by the sum of all three delta resistances. With all three equal to R, RY = R²/(3R) = R/3.
Formula
RY = (R×R)/(R+R+R) = R/3
Step-by-step solution
Correct Answer
B — R/3
Explanation
For delta-to-star conversion, each star resistance equals the product of the two adjacent delta resistances divided by the sum of all three delta resistances. With all three equal to R, RY = R²/(3R) = R/3.
Key Concept
Balanced Delta to Star
Formula
RY = (R×R)/(R+R+R) = R/3
Exam Point
Balanced Δ → Y: divide each resistance by 3.
Exam tip
Balanced Δ → Y: divide each resistance by 3.
Quick method
Balanced Δ → Y: divide each resistance by 3.