Using passive filters for reducing the current harmonics introduced in the line voltage supply by DC motors functioning

In this paper is presented the reduction of the current harmonics at using of the d.c. motor installations. Is studied the behavior of the passive filters at different loads of the motor, as well as the effects of the filter's frequency deviations against the tuning situation on harmonic. This is verified when is used a single-phased transformer, between the three-phased transformer and the load circuit, or in the situation of direct connection between the three-phased transformer and the single-phased rectifying bridge which supplies the d.c. motor. Experiments are made for more values of the d.c. motor's supply voltage for the situation when the isolation transformer is connected.