In dielectric heating, the thyristor circuits consist of
Answer: D
Input ac is rectified and then converted to high frequency ac.
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The amount of dielectric heating is inversely proportional to frequency.
Answer: B
It is proportional to frequency.
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The gate current required to turn on an SCR is
Answer: B
Only a very small gate current is required to trigger SCR into conduction.
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A dc separately excited motor has constant field current. The armature is fed from a single phase supply through a full converter. When a = 0, speed is 500 rpm. If a = 45°, the speed is likely to be
Answer: D
Average output voltage ∝ cos a and therefore reduced to 0.707 of the value for a = 0. Speed is nearly proportional to voltage.
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A single phase full converter gives maximum and minimum output voltage at firing angles of
Answer: A
Output voltage is maximum if a = 0 and is minimum if a = 180°.
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In a parallel inverter
Answer: A
No answer description available for this question
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In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally
Answer: A
Firing angles are kept equal to get symmetrical output voltage.
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A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127 V. When a = 30°, the dc output voltage will be about
Answer: B
NO answer
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In an SCR, the anode current is controlled by
Answer: B
Once SCR has been triggered the gate has no control. Only external resistance controls the anode current.
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Assertion (A): An inverter does not require forced commutation
Reason (R): A series inverter is a forced commutation inverter.
Answer: D
Some inverters require forced commutation.
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