Theory of the D. C. Motor Controlled by Power Pulses Part I - Motor Operation

This paper describes the theoretical relations between currents, fluxes and pulse duration in a DC motor energized by power pulses. From these values, the average torque and speed as well as their instantaneous variations are calculated. The non-linearity of the magnetic circuit is considered by a suitable approximation of the magnetization curve and the resulting error is evaluated. Numerical examples illustrate the characteristics of a shunt and series motor for several types of pulse control. A companion paper1 discusses in detail different braking methods, proprietory commutation phenomenons and additional iron and copper losses. Also, a Fourier analysis of the current pulses is presented.