DEVICE FOR PROTECTING ARMATURE POWER CIRCUIT OF THYRISTOR DRIVE MOTOR AGAINST OPEN CIRCUIT Russian patent published in 1995 - IPC

FIELD: electrical engineering; protection of thyristor drive power circuit against open circuit. SUBSTANCE: device has thyristor converter 1, d.c. motor 2, phase-pulse control unit 3 with speed governor 4, speed governing condition sensor 5, alarm detecting unit 6, armature current sensor 7, first flip-flop 8, field current sensor 9, electromagnetic clutch control unit 10, electromagnetic clutch 11, speed setting element 12, tachogenerator 13. Open circuit in armature circuit stops current flow through armature. Armature current sensor 7 sends logical "0" to input of logical alarm detecting unit 6. Output of speed governor 4 is placed at high potential and speed governor condition sensor 5 places input of logical unit 6 at "1". Logical unit records alarm situation and sends signal through flip-flop 8, that has changed its state, for connecting electromagnetic clutch 11 and disconnecting thyristor converter 1 by shifting thyristor turn-on angles to idle region. EFFECT: improved reliability due to elimination of unwanted operation of protective gear. 1 dwg