DC POWER SUPPLY UNIT FOR ARC FURNACE (OPTIONS THEREOF) Russian patent published in 2008 - IPC H02M7/17 

FIELD: electrical engineering.

SUBSTANCE: in a known DC power supply unit of arc furnace including a three-phase feeding transformer with a power winding and two secondary windings, a first and a second three-phase gate sets with their unipolar DC outputs intended to connect to roof and hearth electrodes of the arc furnace, respectively, between the AC outputs intended to connect to outputs of corresponding secondary windings of transformer a third gate set is connected including six controllable gates with their anodes connected to AC outputs of the first three-phase gate set and cathodes connected to AC outputs of the second three-phase gate set connected in a ring scheme. Both first and second three-phase sets are implemented in the form of three-phase bridge controllable gate circuits (the first option) or three-phase zero controllable gate circuits (the second option). In the later case, one three-phase secondary winding of transformer is connected in "star" topology and another is connected in "reverse star" topology. In accordance with the third option of said technical solution the third gate set is implemented in the form of first and second zero groups each composed of three controllable gates, so as opposite AC outputs formed by connected one to another cathodes of controllable gates of the first group and connected one to another anodes of controllable gates of the second group are connected together, and AC outputs of the first group of controllable gates are connected, respectively, to AC outputs of the first three-phase gate set, AC outputs of the second group of controllable gates are connected, respectively, to AC outputs of the second three-phase gate set.

EFFECT: improvement of cost/performance parameters of entire process plant, extension of service life and lowering cost of routine maintenance in service.

3 cl, 7 dwg, 1 tbl