Chapter 3

D.C. motors


Despite the apparent complexity of the d.c. machine (with its commutator, interpoles, etc.) it is probably the easiest to understand, because the excitation or flux-producing part and the torque producing part are physically distinct. The performance can be studied with the aid of a very simple equivalent circuit, from which many aspects of behaviour can be predicted. The d.c. machine thus makes the ideal learning vehicle, because most of its properties are reflected in all other types.


D.C. motor; Commutator; Armature reaction; Equivalent circuit; Steady-state performance; Transient performance; Torque-speed; Field weakening

3.1 Introduction

Until the 1980s the conventional (brushed) d.c. machine was the automatic ...

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