Question

In a self-commutated SCR circuit, the load consists of $R=10\Omega ,L=10mHandC=10\mu F$. Find the value of time at which SCR will commutate.

• A. 2.012 msec
• B. 0.0993 msec
• C. 0.503 msec
• D. 1.006 msec

Answer 1

The correct option is D 1.006 msec

$R=10\Omega$, $L=10mH$

$C=10\mu H$

${\omega }_0=\frac{1}{\sqrt{LC}}=3.162\times {10}^{3}rad/sec$

$\epsilon =\frac{R}{2L}=500$

${\omega }_r=\sqrt{{\omega }_0^2-{\epsilon }^2}=3122.27rad/sec$

For self commutation time,

$t=\frac{\pi }{{\omega }_r}=\frac{\pi }{3122.217}=1.006msec$