1
GATE EE 2005
+2
-0.6
Consider a phase $$-$$ controlled converter shown in figure The thyristor is fired at an angle $$\alpha$$ in every positive half cycle of the input voltage. If the peak value of the instantaneous output voltage equals $$230$$ $$V,$$ the firing angle $$\alpha$$ is close to
A
$${45^ \circ }$$
B
$${135^ \circ }$$
C
$${90^ \circ }$$
D
$${83.6^ \circ }$$
2
GATE EE 2003
+2
-0.6
A phase - controlled half - controlled single - phase converter is shown in figure. The control angle $$\alpha = {30^ \circ }$$

The output $$dc$$ voltage wave shape will be as shown in

A
B
C
D
3
GATE EE 2002
+2
-0.6
A three phase thyristor bridge rectifier is used in a $$HVDC$$ link. The firing angle $$\alpha$$ (as measured from the point of natural commutation) is constrained to lie between $${5^ \circ }$$ and $${30^ \circ }$$. If the $$dc$$ side current and $$ac$$ side voltage magnitude are constant, which of the following statements is true (neglect harmonics in the $$ac$$ side current and commutation overlap in your analysis)
A
Reactive power absorbed by the rectifier is maximum when $$\alpha = {5^ \circ }$$
B
Reactive power absorbed by the rectifier is maximum when $$\alpha = {30^ \circ }$$
C
Reactive power absorbed by the rectifier is maximum when $$\alpha = {15^ \circ }$$
D
Reactive power absorbed by the rectifier is maximum when $$\alpha = {15^ \circ }$$
4
GATE EE 2002
+2
-0.6
In the single phase diode bridge rectifier shown in fig, the load resistor is
$$R = 50\Omega .$$ The source voltage is
$$V = 200sin\omega t,$$
Where $$\omega = 2\pi \times 50$$ radians per second. The power dissipated in the load resistor $$R$$ is
A
$${{3200} \over \pi }W$$
B
$${{400} \over \pi }W$$
C
$$400\,W$$
D
$$800\,W$$
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