DIRECT-CURRENT DRIVE Russian patent published in 2003 - IPC

FIELD: electrical engineering; stepless starting and speed governing for dc motors fed from ac mains. SUBSTANCE: dc drive has dc commutator motor whose armature winding is shorted out by diode and inserted through isolating diode and power switch between two diagonally opposite terminals of electrical bridge; voltage regulator and voltage divider placed across two diagonally opposite terminals of bridge. Voltage divider output is connected to input of active low-frequency filter and to inverting input of comparator whose output is connected to power switch input; output of active low-frequency filter is connected to input of speed control element and output, to noninverting input of comparator. Additional diode is connected in parallel with low-frequency filter. EFFECT: enhanced reliability. 1 cl, 3 dwg