
3
CONVENTIONAL D.C. MOTORS
INTRODUCTION
Until the 1980s the conventional (brushed) d.c. machine was
the automatic choice where speed or torque control is called
for, and it remains pre-eminent in spite of the growing
challenge from the inverter-fed induction motor. Applica-
tions range from steel rolling mills and railway traction,
through a very wide range of industrial drives through to
robotics, printers and precision servos. The range of power
outputs is correspondingly wide, from several megawatts at
the top end down to a only a few watts, but except for a few of
the small low-performance ones, such as those used in toys,
all have the sam ...