Power Electronics

Exercise: Power Electronics

The phenomenon of overlap in converter operation due to

source resistance

source inductance

both source resistance and source inductance

high value of firing angle

Answer: B

Source inductance delays turn off and hence causes overlap.

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A semiconverter feeding an RLE load operates in

first quadrant only

first and second quadrants

first and fourth quadrants

first and third quadrants

Answer: A

Semiconvertor operates only in first quadrant.

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The amount of dielectric heating is inversely proportional to frequency.

True

False

Answer: B

It is proportional to frequency.

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Two thyristor of same rating and same specifications

will have equal turn on and turn off periods

will have equal turn on but unequal turn off periods

may have equal or unequal turn on and turn off periods

will have unequal turn on and turn off periods

Answer: C

Turn on and turn off times of similar SCRs may not be same.

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In a 3 phase fully controlled converter the firing frequency is

3 times the line frequency

6 times the line frequency

9 times the line frequency

12 times the line frequency

Answer: B

It is a 6 pulse converter.

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