D.C. Motors

UNIT III

Chapter 4

D.C. Motors

Syllabus

Principle of operation, significance of back emf, torque equations and power developed by armature, speed control of DC motors, starting methods of DC motors, load characteristics of DC motors, applications of DC motors

Contents

4.1 Introduction......................4-2

4.2Principle of Operation of a D.C. Motor .....4-2

4.3 Direction of Rotation of Motor.......4-3

4.4Significance of Back E.M.F.............4-4

4.5 Power Equation of a D.C. Motor............4-6

4.6 Torque Equation of a D.C. Motor ...........4-6 May-07,08,09,14,16, April-04, Dec.-07,09,14, Marks 8

4.7 Types of D.C. Motors ............4-10

4.8 D.C. Shunt Motor...................4 10

May-09, Marks 8

4.9 D.C. Series Motor.................4-11

4.10 D.C. Compound Motor...............4 13

4.11 Torque and Speed Equations....................4-14

Oct.-98, April-99, Dec.-05, 06,13,19, May-07, 08,09,11,15,17,19, Marks 16

4.12 D.C. Motor Characteristics....4-19

4.13 Characteristics of D.C. Shunt Motor..............4 19

May-06,14,15, Dec.-09,14,18,19, Marks 6

4.14 Characteristics of D.C. Series Motor ...... 4-20

May-03, 06, 15, Dec.-06, 09, 11, 14, Marks 6

4.15 Characteristics of D.C. Compound Motor ... 4-22

Dec.-14,18, May-15, Marks 4

4.16 Applications of D.C. Motors............4 22

May-15, Marks 3

4.17 Necessity of Starter . . ..............4 23

May-03, 10, 15 Dec.-03, 05,06, 07, 09, 10, 12,13,15, 17, Marks 16

4.18 D.C. Series Motor Starter............4-27

Dec.-05, Marks 8

4.19 Factors Affecting the Speed of a D.C. Motor. ..............4 - 28

4.20 Speed Control of D.C. Shunt Motor....... 4-29 

Nov.-04,Oct.-98 April-97, Dec.-05,06,07,08,14,17,18, May-05,06,07,08,10,11,12,13,14,17,19, Marks 16

4.21 Speed Control of D.C. Series Motor. . . .4-37

May-08, 10, 11,17, 19, Dec.-06, 08, 10, 19, Marks 13

4.22 Ward-Leonard System of Speed Control.... 4-43

Dec.-05,11, Marks 16

4.23 Two Marks Questions with Answers...........4-45