Influence of source and power cord impedance on damping of flux variations induced by commutation in uncompensated universal motors

In this article investigations are carried out in order to analyze the influence of power cord and source impedances on the ability of the field winding of an uncompensated universal motor to damp flux variations caused by the commutation process. The motor is regarded as a harmonic generator with the power cord and the source impedance acting as a load. Rotational tests are carried out with different loads connected to the field winding and the Fourier spectrums of the field voltage are evaluated.