Overcurrent Protection System.
Patent, Filed 27 Jul 81, patented 7 Dec 82,
DEPARTMENT OF THE NAVY WASHINGTON DC
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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 sensinginverse 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 sensinginverse time delay circuit, to drive the power switch, to provide a coupling path for an overcurrent fault signal across electrical isolation interfaces thereof to the logic circuit. Thus, the need for a separate isolated power supply for powering the overcurrent sensinginverse time delay circuit and the need for separate optical andor electromagnetic isolation interfaces for coupling of the overcurrent fault signal are eliminated.
- Electric Power Production and Distribution