7. In the diagram the rms $V_{an} = 100\angle0^\circ$ VAC. Also, $V_{bn} = V_{cn} = 100$ VAC. Three-phase sequence a-b-c.
A
10$\Omega$
$V_R$
B
V
$-j10\Omega$
C
The voltmeter is connected as shown and measures rms $V_{cn}$. The voltmeter has infinite impedance. Draw a phasor diagram with reference to $V_{an}$ and show $V_{bn}$, $V_{cn}$, $V_R$, $V_{ab}$, $V_{ac}$, I on the same diagram. Calculate $V_{ab}$, I, $V_{ac}$, $V_R$, and thus calculate $V_{cn}$. [Answer: $V_{cn} = 176.8\angle-34^\circ$ VAC.]
