DEVICE FOR INDUCTION MOTOR CONTROL AND PHASE-FAILURE PROTECTION Russian patent published in 2004 - IPC

FIELD: electrical engineering; induction motor control and phase-failure protection. SUBSTANCE: proposed device is characterized in that it is suited to use both for electrical installations under design and those operating as device can use magnetic starters and contactors of operating electrical installations. To this end magnetizing coil of starter should be rewound into two sections to provide access to central turn of coil designed for line voltage. Calculations made for some types of size 3 starters have shown that value of capacitors connected in series with sections for starting period is about 2.5 F and that of capacitors connected for entire period when starters are energized is about 0.35 F. Device is controlled by inserting START and STOP buttons or control sensor in central turn circuit. Among advantages of proposed device is that it can be introduced in electrical installation by its attending personnel without waiting for manufacturing double-section coils for magnetic starters and contactors furnished complete with capacitors by specialized enterprises. EFFECT: enhanced reliability of motor protection under phase-failure conditions. 1 cl, 10 dwg