Starting, Speed Control and Braking of Induction Motors

UNIT – IV

Chapter - 7

Starting, Speed Control and Braking of Induction Motors

Syllabus

Needfor starting - Types of starters - DOL, Rotor resistance, Autotransformer and star-delta starters - Speed control - Voltage control, Frequency control and pole changing - Cascaded connection - V/f control - Slip power recovery scheme - Braking of three phase induction motor : Plugging, Dynamic braking and regenerative braking.

Contents

7.1 Introduction

7.2 Necessity of Starter Dec.-07,12, Marks 6

7.3 Types of Starters for Three Phase Induction Motor May-05, 07, 08, 11, 12, 13, 14,16,18 Dec.-04, 05, 10, 11, 12, 14, 15,16,17 Marks 16

7.4 Introduction to Speed Control of Induction Motor

7.5 Supply Frequency Control or V/f Control May-12,13,16,18, Dec.-15,16,17 Marks 8

7.6 Supply Voltage Control  May-16,18, Dec.-16,        Marks         16

7.7 Controlling Number of Poles May-13,16,18, Dec.-14,16,17-     Marks         16

7.8 Adding Rheostats in Stator Circuit      May-16, Dec.-16, Marks         16

7.9 Adding External Resistance in Rotor Circuit... May-2000,16,18 Dec.-06, 10, 13,16          Marks 8

7.10   Cascade Control May-04, 05, 07, 08,11, 12, 13,16,18 Dec.-04, 07,11,16 Marks 16

7.11 Injecting Slip-Frequency E. M. F. into Rotor Circuit      Dec.-17 Marks 7

7.12 Slip Power Recovery Scheme (Static Scherbius System) May-08, 11, 13, 14,16,17 Dec.-07,11,12,13, 14,15,       Marks 16

7.13 Electric Braking of an Induction Motor       Dec.-17 Marks 6

7.14 Two Marks Questions with Answers

7.15 University Questions with Answers (Long Answered Questions)