Electronics and Communication Engineering - Power Electronics
Exercise : Power Electronics - Section 2
26.
Which of these commutation methods uses an auxiliary SCR?
Answer: Option
Explanation:
Class C commutation uses an auxiliary SCR and it is also called auxiliary commutation.
27.
A thyristor needs protection against
high 
high 
both high and high
and high either high or high
or high Answer: Option
Explanation:
Both high and high can destroy SCR.
28.
Two semiconverters are connected in series to form a single phase series converter. The input v = Vm sin ωt and a1 = a2 are the firing angles of the two converters. If a1 = a2 = 0, the dc output voltage is
Answer: Option
Explanation:
Output voltage is for each.
29.
In integral cycle control the period of on-off control should be more than mechanical time constant of load.
Answer: Option
Explanation:
It should be less than mechanical time constant.
30.
A single phase half wave converter is feeding a resistive load. Just before triggering, the voltage across thyristor is
Answer: Option
Explanation:
Before triggering the whole of applied voltage is across SCR and load current is zero.
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