Control circuit for control of a direct-current motor normally excited in series including structure for separate excitation during braking

摘要

A control circuit provides, for connecting a motor to a d.c. voltage source (1), two half bridge (3, 7, 5, 9) each with a respective switch (3, 5) with controlled opening and closing; the first of the half bridge connects a pole of the excitation winding (13) to the source (1) and the second of the half bridge connects a pole of the armature (15) to the source (1). A control unit (11) controls the opening and closing of the two switches (3, 5) of the half bridge and the toggling of the reversing device as a function of the operating conditions of the motor. The control unit (11) is programmed in such a way that in the braking phase it toggles both of the controlled switches (3, 5) cyclically, simultaneously or independently, from an open condition to a closed condition and vice versa.