DC power systems are not very common in the contemporary
engineering practice. However, DC motors still have many practical applications,
such automobile, aircraft, and portable electronics, in speed control
applications. The topics in this lecture presentation are as follows : DC
motors, The simplest DC machine, Commutation in a simple 4-loop DC machine,
Problems with commutation in real DC machines, Solutions to the problems with
commutation, Power flow and losses in DC machines, The losses in DC machines,
The power-flow diagram, Equivalent circuit of a DC motor, Magnetization curve of
a DC machine, Motor types: Separately excited and Shunt DC motors, Shunt motor,
Motor types, Series motor, Cumulatively compounded motors: torque-speed
characteristic, Differentially compounded motors: torque-speed characteristic,
Compounded DC motor, DC motor starters.

**Author(s):** Dr.
Gleb V. Tcheslavski

53**Pages**