Discussion
A balanced Y-connected load having impedance (32 + j24)Ω is connected to 400V, 3-φ supply. Current drawn from the supply will be _____________.
Answer: D
The current drawn is 5.77 A.
In a star connection the line current equals the phase current, and each phase sees the phase voltage, the line voltage divided by \(\sqrt{3}\).
\[ \begin{aligned} V_{ph} &= \frac{400}{\sqrt{3}} \approx 230.9\ \text{V} \\ |Z| &= \sqrt{32^{2} + 24^{2}} = 40\ \Omega \\ I &= \frac{230.9}{40} \approx 5.77\ \text{A} \end{aligned} \]
10 A uses the full line voltage across one phase, which is correct only for a delta load's phase current, and 17.32 A is the line current that delta load would draw. 20.50 A does not come from these values.
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