Question

The secondary line-to-line voltage of a three-phase Y-Y-connected transformer bank is 115 VAC. What would be the secondary line to neutral voltage?
A. 199.2 V

B. 66.4 V

C. 84.2 V

D. 50 V

Answer 1

Answer:

B. 66.4 V

Explanation:

for a Y-Y connection (star connection), the relationship between the line voltages and the phase voltages is governed by the formula:

$V_{L} = \sqrt{3} (V_{ph})$

Where $V_{L}$ = Line Voltage = 115 V (AC there just shows that the current is alternating current )

and $V_{ph}$ = Phase Voltage

⇒  $V_{ph}$ =  $V_{L}$ / $\sqrt{3}$

$V_{ph}$ = 115 / $\sqrt{3}$

$V_{ph}$ = 66.4 V

Hence the secondary Line to neutral voltage is 66.4 Volts