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F1078 Pages: 2

(i) Firing angle for rated motor torque and 750 rpm
(ii) Firing angle for rated motor torque and -500 rpm
(iii) Motor speed for firing angle ೧71609 and rated torque
PART (^
Answer any two full questions, each carries10 marks.
Explain the operation of four quadrant chopper fed separately excited DC motor

drive with necessary diagrams.

Explain the closed loop static rotor resistance control method for the speed
control of a slip ring induction motor. What are the disadvantages of this
method?

Explain the static Kramer scheme for the speed control of a slip ring IM. Explain
the firing angle control of thyristor bridge with constant motor field.
PART D
Answer any two full questions, each carries 10 marks.
With a neat circuit and waveform explain a thyristor based CSI fed IM drive.

Explain how CSI fed IM drive can be used for regenerative braking and
multiquadrant operation.

Explain in detail about the classification of PM synchronous motor?

Explain the field oriented control (FOC) of an AC motor with a block diagram
With a block diagram explain the Micro controller based PMSM drive.

RK

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