Accession Number : ADD013658

Title :   Overcurrent Protection System.

Descriptive Note : Patent, Filed 27 Jul 81, patented 7 Dec 82,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Billings, William W ; Mitchell, James T ; Luebrecht, Richard E

Report Date : 07 Dec 1982

Pagination or Media Count : 8

Abstract : An overcurrent protection system adaptable for use with power controllers of the single or multi-phase ac, or dc types includes a load current sensing element in combination with an overcurrent sensing/inverse time delay circuit, a power switch and a crowbar circuit. The system also includes a drive circuit, a drive circuit input current sensor, a trip signal detector and a logic circuit. The overcurrent protection system, according to the present invention, uses the drive circuit to power the overcurrent sensing/inverse time delay circuit, to drive the power switch, to provide a coupling path for an overcurrent fault signal across electrical isolation interface(s) thereof to the logic circuit. Thus, the need for a separate isolated power supply for powering the overcurrent sensing/inverse time delay circuit and the need for separate optical and/or electromagnetic isolation interfaces for coupling of the overcurrent fault signal are eliminated.

Descriptors :   *CIRCUITS, *ELECTRICAL LOADS, *SWITCHES, *PATENTS, COUPLING(INTERACTION), DETECTION, DRIVES(ELECTRONICS), ELECTRIC CURRENT, ELECTRICAL INSULATION, ELECTROMAGNETISM, INTERFACES, ISOLATION, LOGIC CIRCUITS, PATHS, POWER

Subject Categories : Electric Power Production and Distribution

Distribution Statement : APPROVED FOR PUBLIC RELEASE