N0-BREAK POWER SUPPLY SYSTEM FOR AC CURRENT AND VOLTAGE USERS Russian patent published in 2003 - IPC

FIELD: electrical engineering; no-break power supplies for important users. SUBSTANCE: system designed to supply with power important loads such as numeric-control machine-tools, microprocessor units, and miscellaneous process equipment demanding no-break power supply is provided in addition with third contactor whose contact is connected to like phases of two power lines; one lead of mentioned contactor coil is connected to neutral wire and its other lead, to parallel-and-series junction of auxiliary contacts of switching devices; make contact of first switching device is connected in series with break contact of second switching device; connected in parallel with mentioned contacts are series-interconnected make contact of second switching de vice and break contact of first switching device; connected in series with mentioned parallel-and-series junction is one lead of change-over unit whose other lead is connected to one of phase leads of one of power supplies. Under normal operating conditions induction machines function as motors running at no load to set common shaft in rotary motion. Capacitors are used for correcting reactive power of supply mains to raise its power factor. In this case load, motor, and capacitors are supplied with power from respective lines. Upon occurrence of accident on any line voltage drops across input of faulty line and contactor of the latter turns off. Now asynchronous machine of serviceable line keeps rotating common shaft and that of disconnected line being excited by capacitor bank starts running as generator and feeds load of disconnected line. Load of second line is still fed from this machine. In the process third contactor connects load to serviceable line thereby affording no-break power supply to full load. EFFECT: simplified design, reduced cost, enhanced reliability, and enlarged functional capabilities of system. 1 cl, 1 dwg