SWITCHING UNIT BUILT AROUND SYMMETRICAL THYRISTORS Russian patent published in 2003 - IPC

FIELD: electrical engineering; switching loads in three-phase ac circuits. SUBSTANCE: proposed switching unit has symmetrical thyristors in each phase circuit connected through some leads to output terminals of three-phase current supply; matching unit whose inputs are connected to output terminals of three-phase current supply and outputs, to respective inputs of measurement and check-up unit whose outputs are connected to respective inputs of thyristor control pulse shaper, outputs of the latter being connected through isolating transformers to gate electrodes of symmetrical thyristors; leads of the latter are connected through current transformers to load, to respective inputs of measurement and check-up unit, and to voltage check-up unit and outputs are connected to respective inputs of measurement and check-up unit whose outputs are connected to other inputs of symmetrical thyristor control pulse shaper; measurement and check-up unit is connected to series-connected peripheral device interfacing channel; respective inputs of measurement and check-up unit are connected to some leads of temperature sensors whose other leads are connected to common wire. Checking load voltage and current as well as temperature of symmetrical thyristor case makes it possible to prevent thyristor failure caused by troubles in load. EFFECT: enhanced operating reliability of symmetrical thyristors. 4 cl, 6 dwg