Arc fault detector with circuit interrupter and early arc fault detection
First Claim
1. A circuit interrupting device capable of being electrically connected to an electrical wiring system, between line side phase and neutral conductors and load side phase and neutral conductors, said device comprising:
- switching means for disconnecting a source of electrical power from at least said line side phase conductor to said load side phase conductor;
trigger circuit means for causing said switching means to disconnect the source of electrical power to said load side phase conductor;
means for exciting said trigger circuit means for a predetermined period of time, said predetermined period of time being less than a time needed for said trigger circuit means to cause said switching means to disconnect the source of electrical power to said load side phase conductor; and
first arc fault detecting means for detecting a line impedance associated with the electrical wiring system when said exciting means excites said trigger circuit means, and for generating a line impedance trigger signal when said detected line impedance is greater than a predetermined value.
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Accused Products
Abstract
An arc fault detector comprised as a stand alone unit and in combination with a ground fault circuit interrupter (GFCI) functions to provide protection from potentially dangerous arc fault conditions. When combined with a GFCI, the combination arc fault/ground fault circuit interrupter (AFCI/GFCI) provides protection from both arc fault and ground fault conditions. A single transformer is used to detect faults between neutral and ground and arc faults. An impedance splits the current flow into two portions so as to generate differential current proportional to the current flowing through the conductors. An early arcing detector periodically tests the AC line for high impedance between the device and a main breaker panel. The AFCI/GFCI device detects both AC line frequencies and high frequencies associated with arcing. Both average and instantaneous values of both AC line frequency and high frequency arcing signals are processed to generate an arc fault signal. The device allows the arc detector to differentiate between destructive high level arcing and low level arcing such as generated by typical household appliances and equipment. This serves to decrease the occurrence of false tripping. The device also includes a timer circuit, which permits the user to temporarily disable the arc detector, and includes communication circuitry to permit the device to communicate the occurrence and location of the arc fault to a centralized monitoring station.
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Citations
58 Claims
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1. A circuit interrupting device capable of being electrically connected to an electrical wiring system, between line side phase and neutral conductors and load side phase and neutral conductors, said device comprising:
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switching means for disconnecting a source of electrical power from at least said line side phase conductor to said load side phase conductor; trigger circuit means for causing said switching means to disconnect the source of electrical power to said load side phase conductor; means for exciting said trigger circuit means for a predetermined period of time, said predetermined period of time being less than a time needed for said trigger circuit means to cause said switching means to disconnect the source of electrical power to said load side phase conductor; and first arc fault detecting means for detecting a line impedance associated with the electrical wiring system when said exciting means excites said trigger circuit means, and for generating a line impedance trigger signal when said detected line impedance is greater than a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A circuit interrupting device electrically connected to an electrical wiring system, between line side phase and neutral conductors supplying a source of electrical power and load side phase and neutral conductors supplying the electrical power to at least one load, said device comprising:
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switching means for disconnecting a source of electrical power from at least said line side phase conductor to said load side phase conductor; trigger circuit means for causing said switching means to disconnect the source of electrical power to said load side phase conductor; and arc fault detection means for detecting line impedance based arc fault conditions and generating a line impedance trigger signal to activate said trigger circuit means when a line impedance arc fault condition is detected, and for detecting signal based arc fault conditions and generating a signal level trigger signal to activate said trigger circuit means when a signal based arc fault condition is detected. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. An arc fault circuit interrupter device capable of being electrically connected to an electrical wiring system, between line side phase and neutral conductors and load side phase and neutral conductors, said device comprising:
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a switch connected between at least said line side phase conductor and said load side phase conductor; a trigger circuit operatively connected to said switch such that activation of said trigger circuit causes said switch to disconnect a source of electrical power to said load side phase conductor, and such that excitation of said trigger circuit permits detection of a line impedance associated with the electrical wiring system; and a first arc fault detector capable of exciting said trigger circuit for a predetermined period of time, said predetermined period of time being less than a time needed for said trigger circuit to cause said switch to disconnect the source of electrical power to said load side phase conductor, and said first arc fault detector being capable of detecting said line impedance associated with the electrical wiring system when said trigger circuit is excited, and wherein said first arc fault detector generates a line impedance trigger signal when said detected line impedance is greater than a predetermined value to activate said trigger circuit. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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57. A method for detecting arc faults using a circuit interrupting device comprising:
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detecting the existence of a high impedance based arc fault condition in an electrical wiring system and generating a first arc fault trigger signal in response thereto; sensing current flowing through an electrical load placed on a load side of said device; generating a high frequency signal corresponding to a level of high frequency current flowing through the load; generating an AC line frequency signal corresponding to a level of AC line frequency current flowing through the load; generating a second arc fault trigger signal in response to at least one of said high frequency signal and said AC line frequency signal; and disconnecting a source of electrical power to the load side of the device in response to at least one of said first and second arc fault trigger signals. - View Dependent Claims (58)
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Specification