Two winding resonating arc fault sensor which boosts arc fault signals while rejecting arc mimicking noise
First Claim
1. A sensor for an arc fault detecting device for protecting an electric power circuit including a neutral wire and a hot wire, comprising:
- a transformer with the neutral and hot wires forming primaries;
a first secondary winding wound next to the hot wire, and arranged to receive more of the hot wire flux than the neutral wire flux; and
a second secondary winding wound next to the neutral wire, and arranged to receive more of the neutral wire flux than the hot wire flux;
wherein the first and second secondary windings are connected as signal series adding for common mode currents, and signal series opposing for differential mode currents.
1 Assignment
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Accused Products
Abstract
A fault detector sensor includes a current transformer, with two multi-turn windings each formed around a portion of the core, with one winding adjacent to each of the hot and neutral wires of the power line being protected. Both windings are connected in series in a way which reinforces arc fault noise generated by arc faults involving the line and neutral, but which causes signal reduction for noise signals from the line and neutral, or either, to ground. The windings and core are selected to self resonate at a frequency that excludes power line carrier frequencies but which includes arc fault frequencies. The core optionally has a third winding, forming a grounded neutral transformer, or ground fault detector. Instead of a third winding, one of the arc fault sensing windings can act as a dual function sensor.
45 Citations
48 Claims
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1. A sensor for an arc fault detecting device for protecting an electric power circuit including a neutral wire and a hot wire, comprising:
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a transformer with the neutral and hot wires forming primaries;
a first secondary winding wound next to the hot wire, and arranged to receive more of the hot wire flux than the neutral wire flux; and
a second secondary winding wound next to the neutral wire, and arranged to receive more of the neutral wire flux than the hot wire flux;
wherein the first and second secondary windings are connected as signal series adding for common mode currents, and signal series opposing for differential mode currents. - 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, 28, 29)
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30. An arc fault circuit interrupter for protecting an electric power circuit including a neutral wire and a hot wire, comprising:
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a core having a first winding next to the hot wire which receives more of the hot wire flux than the neutral wire flux;
a second winding next to the neutral wire which receives more of the neutral wire flux that the hot wire flux, wherein the first and second windings are connected as signal series adding for common mode currents, and signal series opposing for differential mode currents. - View Dependent Claims (31)
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32. A combination arc fault and ground fault interrupter for protecting an electric circuit including a neutral wire and a hot wire, comprising:
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a transformer with the neutral and hot wires forming primaries;
a first secondary winding wound next to the hot wire which receives more of the hot wire flux than the neutral wire flux to produce a first signal;
a second secondary winding wound next to the hot wire which receives more of the hot wire flux than the neutral wire flux to produce a second signal;
an arc fault detector for detection of common mode fault currents from hot to neutral; and
a ground fault detector for detection of differential mode fault currents from hot to ground;
wherein the arc fault detector detects first and second signals having a predetermined phase relationship and the ground fault detector detects first and second signals whose phases oppose the predetermined phase relationship. - View Dependent Claims (33, 34, 35, 36, 37, 38)
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39. A combination arc fault and ground fault interrupter for protecting an electric circuit including a neutral wire and a hot wire, comprising:
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a transformer with the neutral and hot wires forming primaries of said transformer;
a center tapped secondary winding wound symmetrically with respect to the neutral and hot wires, with the center tap thus forming two secondary winding segments of said transformer;
an arc fault detector coupled to receive signals from at least one of the secondary winding segments; and
a ground fault detector coupled to receive signals from the entire secondary winding;
wherein the ground fault detector detects differential mode fault currents from hot to ground and the arc fault detector detects common mode faults from hot to neutral. - View Dependent Claims (40, 41, 42, 43, 44)
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45. A sensor for an arc fault detecting device for protecting an electric power circuit including a neutral wire and a hot wire, comprising:
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a transformer with the neutral and hot wires forming primaries of said transformer, and a secondary winding of said transformer wound intermediate the hot wire and neutral wire, wherein the secondary winding senses common mode currents carried by the hot wire, the neutral wire, or both wires which do not involve ground but does not sense differential mode currents carried by the hot wire, the neutral wire, or both wires which involve ground. - View Dependent Claims (46, 47, 48)
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Specification