2 - Practical aspects of DC motors

Abstract

This chapter throws the attention on practical aspects of direct current (DC) motors. DC motors are more complex dynamos than those that operate from alternating current (AC). An exception might be the Faraday disc that provides continuous rotation when powered from a DC source. Once DC motor technology got under way, it matured rapidly and was conveniently available to meet heavy demands as those imposed by the automobile industry, garment manufacturing and, when deployed “backwards,” for generating power for street lighting and general electrification purposes. Currently, DC motors has widespread interest as exceptionally useful devices. This dramatic change has been brought by the advent of solid-state rectifiers, new and exotic magnetic materials, electronic control techniques, electric vehicles, and computers. In addition, electronic control of motors as manifested by chopping techniques, pulse-width modulation, and phase-control tends to obscure the sharp demarcation between DC and AC systems. Therefore, the DC series motor has become the universal motor, operating from both DC and AC with very minor modification.