FIELD: electrical engineering, protection of three- phase motors against asymmetric and partial conditions. SUBSTANCE: proposed gear has electromagnetic starter which supply circuit incorporates break contact of STOP button and limiting element connected in series. Coil of electromagnetic starter is connected ahead of power contacts of starter and power supply source via two make contacts of START button to two phases of network as well as to output of voltage filter of forward sequence. Limiting element comes in the form of coil electromagnetically coupled to another coil connected through choke between neutral point of load and zero point of network. Gear controls voltage of forward and zero sequences and so protects three-phase load against partial and asymmetric conditions of operation which raises functional reliability of electric motor drive as whole. EFFECT: raised functional reliability of electric motor drive as whole. 1 dwg
