In the Wye (Star) connection, the line-to-line voltage is the line-to-neutral voltage multiplied by the square root of 3.

• A. 1.732 (√3)
• B. 0.577
• C. 2.0
• D. 1.0

Answer: (A)

In a Wye connection, the line-to-line voltage is the vector difference between two phase voltages that are 120 degrees apart. If each phase voltage has magnitude V and angles 0° and -120°, the line voltage between those two lines is V_AB = V_AN − V_BN. Its magnitude is sqrt(V^2 + V^2 − 2V^2 cos(120°)) = sqrt(2V^2 − 2V^2(−1/2)) = sqrt(3V^2) = sqrt(3) × V. So the line-to-line voltage equals sqrt(3) times the line-to-neutral (phase) voltage. Numerically, sqrt(3) ≈ 1.732. The other numbers correspond to 1/√3, 2.0, or 1.0, which do not describe this relationship.