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F192071 Pages:2

of 165V (line). Determine converter firing angle for the following operating
points.

(i) Motoring operation at rated motor torque and 1000rpm

(ii) Braking operation at rated motor torque and 1000rpm.

PART ^
Answer any two full questions, each carries10 marks.

List different types of cycloconverters. Explain single phase step down
cycloconverter with circuit diagram and waveforms.
Describe dynamic braking operation of chopper fed separately excited DC motor
drive. Draw speed-torque curves in motoring and braking mode
Describe speed control of induction motors using three phase ac voltage
controller.
What are the slip power recovery control schemes of induction motors. Explain
how static Kramer drive is used to control the speed of induction motors.
PART D

Answer any two full questions, each carries 10 marks.
Discuss the operation of CSI fed induction motor drive. Explain its regenerative
braking and multi-quadrant operation.
Give the concept of basic transformation in reference frame theory applied to
induction motors.
Explain in detail about self-control mode of operation of synchronous motor
With block diagram, explain the operation of microcontroller based permanent

magnet synchronous motor drives.

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