ELECTRIC DRIVE OF CRANE LOAD LIFTING AND LOWERING MECHANISM Russian patent published in 2007 - IPC B66C13/22 

FIELD: mechanical engineering; load-handling facilities.

SUBSTANCE: invention relates to multimotor electric drives of load-lifting cranes. Main electric motor has phase-wound rotor, and auxiliary two-speed electric motor is installed on its shaft. Drive is furnished with brake pushers electric motors, master controller with lifting, lowering and speed step change-over circuits of main electric motor, electric motor control unit, line contactor and speed change over contactors, load lifting and lowering low and high speed contactors and dynamic braking contactor. Master controller and electric motors control unit are connected with power source. Stator of brake pushers electric motor are connected to like phases of main electric motor which are connected to supply main. High and low speed windings of auxiliary motor are connected to like phases of stator winding of main electric motor. Electric drive is furnished with three=phase bridge rectifier, main and additional resistors. First leads of main resistors are connected with phase leads of rotor winding of main electric motor, first leads of additional resistors are interconnected, and their second leads are connected to ac leads of rectifier. Electric drive is furnished with resistor unit. First leads of resistors of each group are connected with second lead of resistor of corresponding phase of rotor winding of main electric motor which is connected with second lead of resistor of corresponding group of resistor unit. The latter is connected to second leads of two other resistors of said group and is connected to corresponding lead of rectifier. Groups of resistors are interconnected by second leads of resistors, and cathode lead of rectifier is connected with electric drive through maximum current relay and dynamic braking diode. One resistor is connected with first phase of stator winding of main electric motor whose third phase is connected with anode lead of rectifier. Minimum current relay is connected to first and third phases of main electric motor through second dynamic braking diode.

EFFECT: reduced wear of electric drive, increased service life and reliability.

6 dwg