ABSTRACT
Brush–commutator electric machines are d.c. (or PM) excited on the stator with the rotor containing coils(in slots of a laminated silicon–iron core) whose ends are connected to copper insulated segments on the rotor which has brushes for d.c. output generator mode and vice versa for motor mode, when fed from a d.c. source with variable voltage level.
Stator and rotor construction elements, brush–commutator windings (with case studies), the brush commutator airgap flux density of stator d.c. excitation (or of permanent magnets) no-load magnetization curve (with a numerical example), airgap flux density of armature (a.c. rotor) winding (by example), the commutation process, the a.c. rotor coil inductance, emf, equivalent circuit, and d.c. excitation connections, d.c. brush motor (generator characteristics) with separate (or PM) d.c. excitation, d.c. brush PM motor characteristics, and control methods (via a numerical example)––for a lab session––d.c. brush series motor (lab. session) characteristics (for a lab session), a.c. brush (universal) motor characteristics, d.c. brush machine testing, losses, efficiency, cogging torque, and a preliminary extended design (sizing) methodology (via a case study) are all presented in the chapter which contains also a summary and a few proposed problems (with solving hints) for the end (106 distinct equations + 46 figures).
With the accent on the brush PM motor still in wide use (from windshield wipers to robotics), this chapter illustrates fundamental aspects usable for a.c. (induction and synchronous) basic electric machines as well as their recent breeds: multiphase machines, flux-modulation machines, with rotary and linear motion, all presented in subsequent Chapters
