Q. Assertion (A): Snubber circuit has an RC series circuit in parallel with SCR

Reason (R): Voltage across a capacitor can not change instantaneously.

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Q. In dielectric heating, the thyristor circuits consist of

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Q. On load tap changer using thyristors can have a maximum of two taps.

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Q. Assertion (A): A cycloconverter may be line commutated or forced commutated

Reason (R): A step up cycloconverter requires forced commutation.

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Q. When thyristors are connected in series and parallel, it may be necessary to have :

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Q. A single phase half wave regulator uses

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Q. A Shockley diode can be used

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Q. An SCR has a turn on time of 4 μs. The gate pulse should have a duration of about

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Q. In a multiphase chopper, the different choppers operate in

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Q. In a dual converter both converters work as rectifiers.

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Q. A single phase full wave regulator feeds R-L load. The best gating signal is

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Q. A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if

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Q. A cycloconverter cannot give a frequency higher than input frequency.

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Q. A thyristor has internal power dissipation of 40W and is operated at an ambient temperature of 20°C. If thermal resistance is 1.6° C/W, the junction temperature is

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Q. In a single phase dual converter, α1, and α2 are firing angles of the two converters. Then

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Q. The number of gates in an SCR is

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Q. The waveshape of output voltage of half bridge inverter is

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Q. A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the speed is 1440 rpm. At 25 Hz, the speed is likely to be

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Q. The gate current required to turn on an SCR is

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Q. Assertion (A): A high dv/dt may cause triggering of a thyristor.

Reason (R): A high dv/dt results in charging current in the thyristor.

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