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C5809 Pages:

A single phase semi-converter fed from 120 V, 50 Hz supply is connected to a
load resistance of 10 Q. If the average output voltage is 25% of its maximum
possible average output voltage, find the circuit turn off time.

PART C

Answer any two full questions, each carries 10 marks
Draw the circuit for three phase full converter feeding RLE load. Sketch the
output voltage waveform for a firing angle of 60°.
A three-phase half-wave controlled converter is connected to 380 V (line)
supply. If the load current is constant at 32 A independent of the firing angle and
on state forward drop of SCRs is 1.2 V, Find:
i) Peak reverse voltage rating of SCRs
ii) Average power dissipation in each SCR
Explain the basic working of an ideal Dual converter and its four-quadrant
operation.
A single-phase half bridge inverter has a resistive load of 10 Q, and a center-tap
60 input voltage of 96 V. Obtain the Fourier series representation of the output
voltage waveform and hence find the value of distortion factor.
Explain the 120°conduction mode of a three-phase bridge inverter with output
voltage waveforms, indicating the devices conducting in each state.

PART D

Answer any two full questions, each carries 10 marks
Explain the operation of single phase voltage controller with RL load with output
voltage and current waveforms.
For a single-phase voltage controller, develop a relationship between conduction
angle and firing angle. Under what condition conduction angle equals 7?
Design a simple light dimmer circuit using TRIAC including the trigger circuit.
Explain the working of Two quadrant (Class C) chopper, with relevant
waveforms.
Derive the expression for output voltage of a Buck-Boost regulator, showing
relevant waveforms.
The switches in the figure are operated alternatively, each switch being on for
half of each cycle. Determine the relationship between ‏ج۷‎ and Voyt .

اد ‎೫ ೫‏ اد

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