METHOD FOR CONTROLLING LOAD-LIFTING ELECTROMAGNET Russian patent published in 2004 - IPC

FIELD: electrical engineering; supplying load-lifting electromagnets with power and controlling their operation. SUBSTANCE: method includes supply of high voltage during electromagnet closing to boost up its magnetizing process and to speed up load gripping, its magnetization by regulated rectified current for load holding and carrying, and demagnetization for load dropping. Current is checked during magnetization and upon end of boosting electromagnet is changed over to magnetizing current stabilization mode; in the course of load holding voltage across electromagnet is checked and if it is beyond permissible limit, its circuit is changed over to voltage stabilization mode for its continuous running. Current is checked up for positive and negative power circuits of electromagnet, current difference is evaluated, and if current difference exceeds its specified level, electromagnet is turned off. EFFECT: reduced heating of electromagnet coil, enlarged continuous running time, enhanced operating reliability of equipment used. 2 cl, 1 dwg