Question 232: AC fundamentals

Question

An arc lamp requires a direct current of
10 A at 80 V to function. If it is connected
to a 220 V (rms), 50 Hz AC supply, the
series inductor needed for it to work is
close to :

Accepted Answer

From the circuit, we have
$$R = {{80} \over {10}} = 8\,\Omega $$
$$10 = {{220} \over {\sqrt {{R^2} + X_L^2} }} \Rightarrow \sqrt {64 + X_L^2}  = 22$$
$$ \Rightarrow X_L^2 = 484 - 64 = 420$$
$$ \Rightarrow {X_L} = \sqrt {420}  = 20.5\,\Omega $$
$$ \Rightarrow \omega L = 20.5$$
$$L = {{20.5} \over {2\pi  	imes 50}} = {{20.5} \over {314}} = 0.065\,H$$

Answer

0.044 H

Answer

0.065 H

Answer

80 H

Answer

0.08 H

AC fundamentals

An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V (rms), 50 Hz AC supply, the series inductor needed for it to work is close to :

Choose the correct answer: