A three-phase induction motor operating from a power supply of constant frequency can be used to supply a range of speed by variation of (a) The magnitudes of the terminal voltages, or (b) The magnitudes of the secondary circuit resistances. Sketch motor torque-speed characteristics to demonstrate each of these control methods, showing intersections with load line representing a constant torque requirement of about rated torque. Point out the relative features of the two schemes for speed control purposes in this case. Show, by diagrams, how pairs of thyristors connected in the inverse- parallel arrangement may be used to obtain speed control by each of the two methods. Explain the scheme of thyristor triggering that you would recommend. What particular difficulties would you anticipate in correctly triggering the thyristors to obtain secondary resistance control?

A three-phase induction motor operating from a power supply of constant frequency can be used to supply a range of speed by variation of (a) The magnitudes of the terminal voltages, or (b) The magnitudes of the secondary circuit resistances. Sketch motor torque-speed characteristics to demonstrate each of these control methods, showing intersections with load line representing a constant torque requirement of about rated torque. Point out the relative features of the two schemes for speed control purposes in this case. Show, by diagrams, how pairs of thyristors connected in the inverse- parallel arrangement may be used to obtain speed control by each of the two methods. Explain the scheme of thyristor triggering that you would recommend. What particular difficulties would you anticipate in correctly triggering the thyristors to obtain secondary resistance control?

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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