SYSTEM FOR ROTOR FREQUENCY VARIATION AND SPEED CONTROL IN ASYNCHRONOUS AND SIMULTANEOUS WAY FOR SEVERAL ELECTRIC MOTORS DRIVEN BY ONE INVERTER Russian patent published in 2013 - IPC H02P5/48 H02P5/50 H02P27/05 

FIELD: electrical engineering.

SUBSTANCE: system for frequency variation and speed control contains a group of electric motors, a group of rectifiers, a group of breakers, a group of diodes, a group of current limiters, a group of capacitors, full bridge or half-bridge, a group of feedback voltage detectors for detecting against speed, a group of feedback voltage detectors for detecting against current. Using the theory of inverted control voltage at the output of the inverter with full bridge or half-bridge is used as additional retroactive electromotive force for electric motors with different functions as per the rated power of the motor, at that different breakers are used for asynchronous and simultaneous actuation of electric motors implementing movements of lifting, forward and back, turn and travel by a cargo crane. When a cargo crane lifts a cargo then extra electric energy is returned to the eclectic motor through the inverter; when a cargo crane lowers a cargo the electric motor generates electric energy which is delivered to voltage inverter in order to return electric energy.

EFFECT: simplification, reduction of weight, costs, improvement of reliability and energy saving.

7 cl, 4 dwg