Arc detection system
First Claim
1. An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system, the line carrying a current when a path is provided for current flow, the path either provided by the line without a break or by an arc across the break in the line, with no current path being provided when the break is present and no arc is present, the arc detector comprising:
- a current sensor coupled to the line carrying the current, for measuring a current amplitude and providing a current signal proportional to said current amplitude;
a filtering amplifier for amplifying only desired frequency components of said current signal into an amplified signal and for rejecting unwanted low frequency components, wherein arc pulses form steep clock edges in said amplified signal; and
an accumulator, coupled to an output of said filtering amplifier and having a reset input, for counting said steep clock edges in said amplified signal, said accumulator asserting a detection signal at an output node when said accumulator accumulates a predetermined threshold number of clock edges, said accumulator beginning an accumulation of clock edges after a reset signal is asserted at said reset input to said accumulator.
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Accused Products
Abstract
An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system. Normally, the line carries current, but when the line is broken, current doesn'"'"'t flow until an arc occurs across the break. The arc detector detects the break using a current sensor for measuring the current, a filter for filtering out unwanted frequencies, an amplifier for amplifying the remaining frequencies into a substantially square wave, a counter for counting square wave transitions, and a latch to hold a detection signal at an output node when the counter counts a preset number of square wave transitions without being reset by a reset switch or a periodic oscillator.
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Citations
13 Claims
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1. An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system, the line carrying a current when a path is provided for current flow, the path either provided by the line without a break or by an arc across the break in the line, with no current path being provided when the break is present and no arc is present, the arc detector comprising:
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a current sensor coupled to the line carrying the current, for measuring a current amplitude and providing a current signal proportional to said current amplitude; a filtering amplifier for amplifying only desired frequency components of said current signal into an amplified signal and for rejecting unwanted low frequency components, wherein arc pulses form steep clock edges in said amplified signal; and an accumulator, coupled to an output of said filtering amplifier and having a reset input, for counting said steep clock edges in said amplified signal, said accumulator asserting a detection signal at an output node when said accumulator accumulates a predetermined threshold number of clock edges, said accumulator beginning an accumulation of clock edges after a reset signal is asserted at said reset input to said accumulator.
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2. An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system, the line carrying a current when a path is provided for current flow, the path either provided by the line without a break or by an arc across the break in the line, with no current path being provided when the break is present and no arc is present, the arc detector comprising:
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a current transformer coupled to the line carrying the current, for measuring a current amplitude and providing a current signal proportional to said current amplitude; a filtering amplifier for amplifying only desired frequency components of said current signal into an amplified signal and for rejecting unwanted low frequency components, wherein arc pulses form steep clock edges in said amplified signal; and an accumulator, coupled to an output of said filtering amplifier and having a reset input, for counting said steep clock edges in said amplified signal, said accumulator asserting a detection signal at an output node when said accumulator accumulates a predetermined threshold number of clock edges, said accumulator beginning an accumulation of clock edges after a reset signal is asserted at said reset input to said accumulator. - View Dependent Claims (3)
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4. An arc detector for detecting electrical arcs across a break in a line carrying a current in an electrical system, the line carrying a current when a path is provided for current flow, the path either provided by the line without a break or by an arc across the break in the line, with no current path being provided when the break is present and no arc is present, the arc detector comprising:
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a current sensor coupled to the line carrying the current, for measuring a current amplitude and providing a current signal proportional to said current amplitude; a filter for filtering out unwanted frequency components from said current signal; an amplifier for amplifying said current signal into an amplified signal by a factor sufficient that desired frequency components which were not filtered out of said current signal by said filter form steep clock edges in said amplified signal; a counter, coupled at a clock input to said amplifier and having a reset input, for counting said steep clock edges in said amplified signal, said counter asserting a detection signal at an output node when said counter counts up to a predetermined threshold number, said counter beginning a count to said predetermined threshold number after a reset signal is asserted at said reset input; a reset circuit coupled to said reset input for resetting said counter in response to any one of a set of predetermined reset conditions; and a latching circuit coupled to said output node and said counter for disabling said clock input when said detection signal is asserted. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification