A D.C. motor model including armature reaction

In a d.c. machine the armature reaction reduces the total flux per pole because of saturation effects at heavy armature currents. In this project the separately excited d.c. motor is modelled by considering the total flux per pole as a function of armature and field currents. The machine model is linearized so that it is valid only for small changes in the neighbourhood of steady state conditions. The machine model when represented in the matrix form is a set of first order differential equations in which changes in the armature voltage, field voltage and load torque are the inputs, whereas changes in the armature current, field current and motor speed represent the response of the machine. [Continues.]