Arc fault circuit interrupter for a compressor load
First Claim
1. An arc fault circuit interrupter comprising:
- a line terminal adapted to receive a line voltage including a zero crossing;
a load terminal;
separable contacts electrically connected between said line terminal and said load terminal;
a current sensor adapted to sense current flowing between said line terminal and said load terminal and through said separable contacts, said sensed current including a line cycle;
an arc fault detection circuit adapted to collect a plurality of samples of said sensed current for said line cycle, determine a first slope of said sensed current at about the zero crossing of said line voltage, determine a magnitude of one of said samples at about said zero crossing, determine a second slope of said sensed current at another one of said samples having about said magnitude, said first slope being opposite in polarity with respect to said second slope, calculate a difference between said first and second slopes, and generate a trip signal as a function of said difference; and
an operating mechanism adapted to open said separable contacts responsive to said trip signal.
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Accused Products
Abstract
An arc fault circuit interrupter includes separable contacts electrically connected between line and load terminals, and a current sensor adapted to sense current flowing between the terminals and through the contacts. An arc fault detection circuit is adapted to collect a plurality of samples of the sensed current for a line cycle, determine a first slope of the sensed current at about a zero crossing of a line voltage, determine a magnitude of one of the samples at about the zero crossing, determine a second slope of the sensed current at another one of the samples having about the magnitude, with the first slope being opposite in polarity with respect to the second slope. The arc fault detection circuit calculates a difference between the slopes, and generates a trip signal as a function of the difference. An operating mechanism is adapted to open the contacts responsive to the trip signal.
40 Citations
19 Claims
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1. An arc fault circuit interrupter comprising:
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a line terminal adapted to receive a line voltage including a zero crossing;
a load terminal;
separable contacts electrically connected between said line terminal and said load terminal;
a current sensor adapted to sense current flowing between said line terminal and said load terminal and through said separable contacts, said sensed current including a line cycle;
an arc fault detection circuit adapted to collect a plurality of samples of said sensed current for said line cycle, determine a first slope of said sensed current at about the zero crossing of said line voltage, determine a magnitude of one of said samples at about said zero crossing, determine a second slope of said sensed current at another one of said samples having about said magnitude, said first slope being opposite in polarity with respect to said second slope, calculate a difference between said first and second slopes, and generate a trip signal as a function of said difference; and
an operating mechanism adapted to open said separable contacts responsive to said trip signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification