ELECTRIC DRIVE OF LOAD-LIFTING CRANE SLEWING 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 machines. Proposed electric drive contains induction motors with phase wound rotors, of brake hydraulic pusher, master controller with control circuits connected with supply line. Connected to the latter is also electric drive control unit with clockwise and counter-clockwise rotation contactors, speed step change-over contactors, acceleration contactors, time relay, clockwise and counter-clockwise rotation memory relays and also circuit consisting of speed control pickup and rotation frequency relay. Stator windings of electric motors with phase-wound rotors are interconnected by like leads and are connected to system according to plugging scheme. Maximum current relay is connected to one of phases of stator winding of each motor with phase-wound rotor. Each motor with phase-wound rotor is furnished with unit of multistep resistors some leads of each of which being connected with corresponding phase leads of rotor winding of electric motor, and second leads of resistors are connected into star through semistors of switch. Switch control unit includes to bridge rectifiers whose inputs are connected to outputs of semistor switches, accordingly, and are shunted by contacts to prevent cutting-in of acceleration contactors at plugging of induction motors in period of time corresponding to reduction of speed to minimum value. Inductive sensor of drive brake pulley rotation speed control is mechanically coupled with shaft of one electric motors with phase-wound rotor and electrically connected with supply line of master controller.

EFFECT: reduced dynamic loads, wear and power consumption.

3 dwg