ELECTRIC BRAKE AND DRAW-WORKS BIT FEEDER DRIVE ASSEMBLY Russian patent published in 2004 - IPC

FIELD: boring equipment; draw-works. SUBSTANCE: assembly has slip-ring induction motor whose stator winding is connected to brake resistors and rotor winding, to frequency changer. During drill-bit running at high speed induction motor operates to afford dynamic braking. Motor braking torque is adjusted by field current supplied from frequency changer. Motor braking torque is maintained within comprehensive speed range by means of brake resistors made of ferromagnetic material. At low speeds frequency changer is switched over to run as inverter, and motor operates in regenerative braking mode. In order to ensure flatter mechanical characteristics at low speeds, brake resistors are closed through contactor. Proposed assembly is designed for operation as generator and as motor under emergency lifting conditions and as bit feed regulator during boring operations which facilitates control of draw-works during its drill-bit running. EFFECT: enlarged functional capabilities of assembly. 1 cl, 1 dwg