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 starting torque is 100 N-m. At 25 Hz, the starting torque

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Q. In a three phase to single phase full wave bridge cycloconverter, the number of thyristors is

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Q. In a cycloconverter it is possible to vary

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Q. Lead mounting for SCR is used for

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Q. A load commutated chopper circuit has

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Q. Assertion (A): The output voltage of an inverter can be controlled by PWM technique

Reason (R): In a current source inverter the input current is constant.

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Q. A TRIAC is equivalent to

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Q. Which of the following commutation methods is the overall circuit under damped?

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Q. Assertion (A): SUS is a PUT and avalanche diode connected between gate and cathode

Reason (R): SBS has two SUS inbuilt together and connected in anti-parallel

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Q. In a single phase full wave controlled rectifier using centre tap transformer, the voltage across each half of secondary is Vm sin ωt. The peak inverse voltage is

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Q. Which statement is correct?

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Q. In a three phase series inverter, the firing frequency is

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Q. A 3 phase fully controlled converter is a

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Q. A cycloconverter is a group of controlled rectifiers.

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Q. A single phase full wave regulator feeds a resistive load. The firing angle of thyristors is 90°. The input power factor is

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Q. The leads in a TRIAC are denoted by

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Q. A step down cycloconverter has an input frequency f. If it uses natural commutation, the output frequency

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Q. In a single phase full wave regulator, the rms current in each thyristors is Ir The run load current is equal to

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Q. In a half bridge inverter, the freewheeling diodes are needed

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Q. When a thyristor is conducting, the voltage drop across it

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