DC DRIVE Russian patent published in 1997 - IPC

FIELD: DC motor speed control when power is supplied from ac mains. SUBSTANCE: DC drive has DC commutator motor whose armature winding is shorted out by diode and is connected through power switch across diagonally opposite terminals of rectifier bridge, voltage regulator whose input is connected to inverting input of comparator. Comparator output is connected to power switch input; it also has speed setting element whose output is connected to noninverting input of comparator. Newly introduced in electric drive are diode and low-frequency active filter whose input is connected output of voltage divider connected across diagonally opposite terminals of rectifier bridge; output of low-frequency active filter is connected to input of speed setting element; armature winding is connected, together with power switch, across diagonally opposite terminals of rectifier bridge, through additional diode. EFFECT: improved stability of speed control. 2 dwg