Low cost apparatus for detecting arcing faults and circuit breaker incorporating same
Patent 5691869 Issued on November 25, 1997. Estimated Expiration Date: 
June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3515943 3654519 Arc detector for electric rod furnace Trip delay override for electrical circuit breakers Arcing fault detector Method and apparatus for detecting arcing in electrical connections by monitoring high frequency noise Electronic circuit breaker with protection against sputtering arc faults and ground faults Circuit breaker with protection against sputtering arc faults Patent #: 5307230 InventorsApplicationNo. 471132 filed on 06/06/1995US Classes:361/42, Ground fault protection361/94With time delay protective meansExaminersPrimary: Gaffin, JeffreyAssistant: Leja, Ronald W. Attorney, Agent or FirmForeign Patent References
International ClassH02H 003/00AbstractA low cost analog arcing detector and a circuit breaker incorporating such a detector provide a variable response time to arcing faults based upon the amplitude of the arcing current. A filter generates pulses having an amplitude proportional to the amplitude of the step increase in current generated by the striking of the arc. The pulses are rectified and the amount by which the single polarity pulses exceed a threshold value, selected to eliminate nuisance trips on current step increases characteristic of some common loads, is integrated by a capacitor connected to a resistor which continually adjusts the capacitor voltage in a sense opposite to that of the pulses. The capacitor and resistor are selected to generate a trip signal as a function of the accumulated, time attenuated magnitude of the step increases in current associated with each striking of the arc current. Preferably, the pulses are squared before the reference current is subtracted to provide faster response for large amplitude arc currents, while avoiding false trips caused by known loads. Preferably, the arcing detector is used with a ground current detector which provides further protection by tripping on ground currents flowing through carbon tracks deposited by arcing currents below the threshold of the arcing fault detector.Other References
Field of SearchGround fault protectionWith more than two wires In a polyphase system In a single phase system With more than two wires With more than three wires With current and voltage responsive fault sensors With phase sequence network analyzer With specific quantity comparison means Voltage and current Distance relaying With time delay protective means Voltage Current With specific voltage responsive fault sensor With time delay protective means With sampler With plural mixers With filtering Bandpass By frequency sensitive or responsive detection By phase sensitive or responsive detection By voltage or current measuring For insulation fault For insulation fault | |
