Numerical investigation of the DC electric motor

We analyze the motion of a simple DC brushed electric motor: a rotating loop of current (rotor) with a commutator in the presence of a constant uniform magnetic field (stator). We solve numerically the equations of motion and investigate the different characteristics of the solution space. For some values of the parameters, simple asymptotic steady-state solutions can be found. In particular we obtain expressions for the terminal angular speed, relaxation time, average power, and efficiency in the steady-state. (paper)