Accession Number : ADD003684

Title :   Low Power Solid State Three-Phase Overcurrent/Undercurrent Protection Circuit.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON D C

Personal Author(s) : Hudak,Joseph M

Report Date : 01 Feb 1977

Pagination or Media Count : 7

Abstract : Each phase of the power input circuit in a three-phase electrical system is coupled to a sensor by means of a pick-off transformer. Each sensor has an overcurrent detection circuit comprising a slow response filter, an operational amplifier, and a comparator and an undercurrent detection circuit comprising a fast response filter, an operational amplifier and a comparator. A fourth overcurrent detecting sensor is coupled to a selected system feed circuit. A C/MOS logic circuit responds with a high state output when any number of sensor network outputs go to the high state. The output of the C/MOS logic circuit is filtered by a slow response filter and is used to trigger an actuating circuit that operates a standby breaker in the system input circuit.

Descriptors :   *Patents, *Current limiters, Solid state electronics, Transformers, Circuit breakers, Phase(Electronics), Complementary metal oxide semiconductors, Low power, Overload, Comparators

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE