DEVICE FOR SELECTIVE PROTECTION OF THREE-PHASE CONSUMERS FROM UNBALANCED OPERATING CONDITIONS Russian patent published in 2009 - IPC H02H7/08 

FIELD: electricity.

SUBSTANCE: invention relates to electric engineering; it can be used for selective protection of three-phase consumers from unbalanced operating conditions. Device contains contactor starter with one coil lead connected to zero conductor in network and the other coil lead - to phase through Stop button and optical bidirectional thyristor; light-emitting diode in control circuit of optical bidirectional thyristor is connected through current-limiting resistor and auxiliary diode bridge to common point between serial-connected capacitor and resistor with inductance coil and to the second retarding phase switched between power contacts of starter and power consumer. Besides, capacitor is connected by uncommon lead to the first phase in network and resistor is connected by uncommon lead to the third leading phase; capacitor is switched in parallel to anode and cathode of diode bridge and Stop button is switched in parallel to optical bidirectional thyristor.

EFFECT: increase of device safety level and provision of operational selectivity with short circuit protection device for power consumers.

1 dwg