US5224006A — Electronic circuit breaker with protection agains…

Claim 1

Independent Claim 130 words

Apparatus for protecting an electrical system having a line conductor and a grounded neutral conductor, said apparatus comprising: common sensing means sensing current in said neutral conductor wherein said common sensing means comprises di/dt sensing means generating a di/dt signal representative of a rate of change of current in said grounded neutral conductor, ground fault detector means responsive to current in said neutral conductor as sensed by said common sensing means to generate a trip signal in response to a ground fault; line-to-neutral fault detector means responsive to current in said neutral conductor as sensed by said common sensing means to generate a trip signal in response to line-to-neutral faults in said electric system; and trip means responsive to said trip signals to interrupt current flow in said electrical system.

Claim 2

Dependent Claim 130 words

Apparatus for protecting an electrical system having a line conductor and a grounded neutral conductor, said apparatus comprising: common sensing means sensing current in said neutral conductor wherein said common sensing means comprises di/dt sensing means generating a di/dt signal representative of a rate of change of current in said grounded neutral conductor, ground fault detector means responsive to current in said neutral conductor as sensed by said common sensing means to generate a trip signal in response to a ground fault; line-to-neutral fault detector means responsive to current in said neutral conductor as sensed by said common sensing means to generate a trip signal in response to line-to-neutral faults in said electric system; and trip means responsive to said trip signals to interrupt current flow in said electrical system.

Claim 3

Dependent Claim 35 words

The apparatus of claim 1 wherein said ground fault detector means is a dormant oscillator ground fault detector including a second sensing means sensing a difference in current in said line conductor and neutral conductor.

Claim 4

Dependent Claim 78 words

The apparatus of claim 1 wherein said line-to-neutral detector means includes bandwidth limiting means bandwidth limiting said di/dt signal to generate a bandwidth limited di/dt signal and comparator means comparing said bandwidth limited di/dt signal to a first threshold signal and generating said trip signal when said bandwidth limited di/dt signal exceeds a first threshold, said bandwidth limiting means having a bandwidth selected to provide a predetermined relative sensitivity between overcurrent line-to-neutral faults and sputtering arc line-to-neutral faults.

Claim 5

Dependent Claim 59 words

The apparatus of claim 3 including delayed trip signal generating means responsive to said bandwidth limited di/dt signal to generate a delayed trip signal in response to a persistent bandwidth limited di/dt signal of a preselected average value and wherein said trip means is also responsive to said delayed trip signal to interrupt current flow in said electrical system

Claim 6

Dependent Claim 61 words

The apparatus of claim 3 wherein said ground fault detector means is a dormant oscillator ground fault detector which resonates at a predetermined resonant frequency in response to a ground fault and wherein said bandwidth limiting means in said line-to-neutral fault detector means has a pass band which does not include the resonant frequency of said dormant oscillator ground fault detector.

Claim 7

Dependent Claim 99 words

A circuit breaker for protecting an electrical system from both overcurrent faults having substantially sinusoidal waveforms and sputtering arc faults having substantially step waveforms, said circuit breaker comprising: current sensing means sensing current flowing in said electrical system; trip signal generating means responsive to current sensed by said current sensing means to generate a trip signal in response to current of a first magnitude with a substantially sinusoidal waveform and in response to current of a second magnitude with a substantially step waveform; and trip means responsive to said trip signal to interrupt current flow in said electrical system.

Claim 8

Dependent Claim 99 words

A circuit breaker for protecting an electrical system from both overcurrent faults having substantially sinusoidal waveforms and sputtering arc faults having substantially step waveforms, said circuit breaker comprising: current sensing means sensing current flowing in said electrical system; trip signal generating means responsive to current sensed by said current sensing means to generate a trip signal in response to current of a first magnitude with a substantially sinusoidal waveform and in response to current of a second magnitude with a substantially step waveform; and trip means responsive to said trip signal to interrupt current flow in said electrical system.

Claim 9

Dependent Claim 74 words

The circuit breaker of claim 6 wherein said trip signal generating means includes means generating a trip signal in response to current with a substantially sinusoidal waveform having a third magnitude which is less than said first magnitude and which persists for a selected time interval, and in response to current with a substantially step waveform having a fourth magnitude which is less than said second magnitude which persists for a selected time interval.

Claim 10

Dependent Claim 100 words

A circuit breaker for protecting an electrical system from both overcurrent faults and sputtering arc faults, said circuit breaker comprising: sensing means generating a di/dt signal representative of the rate of change of current in said electrical system; bandwidth limiting means bandwidth limiting said di/dt signal to generate a bandwidth limited di/dt signal; comparison means comparing said bandwidth limited di/dt signal to an instantaneous trip reference signal and generating a trip signal when said bandwidth limited di/dt signal exceeds said instantaneous trip reference signal; and trip means interrupting current flow in said electrical system in response to said trip signal.

Claim 11

Dependent Claim 100 words

A circuit breaker for protecting an electrical system from both overcurrent faults and sputtering arc faults, said circuit breaker comprising: sensing means generating a di/dt signal representative of the rate of change of current in said electrical system; bandwidth limiting means bandwidth limiting said di/dt signal to generate a bandwidth limited di/dt signal; comparison means comparing said bandwidth limited di/dt signal to an instantaneous trip reference signal and generating a trip signal when said bandwidth limited di/dt signal exceeds said instantaneous trip reference signal; and trip means interrupting current flow in said electrical system in response to said trip signal.

Claim 12

Dependent Claim 41 words

The circuit breaker of claim 8 wherein said bandwidth limiting means has means of determining a bandwidth of said bandwidth limited di/dt signal selected to provide a selected relative sensitivity of said comparison means to overcurrent faults and sputtering arc faults.

Claim 13

Dependent Claim 37 words

The circuit breaker of claim 9 including full wave rectifying means full wave rectifying said bandwidth limited di/dt signal and wherein said comparison means compares said full wave rectified bandwidth limited di/dt signal to said reference signal.

Claim 14

Dependent Claim 57 words

The circuit breaker of claim 9 including delay means generating a delayed bandwidth limited di/dt signal from said bandwidth limited di/dt signal and additional comparison means comparing said delayed bandwidth limited di/dt signal to a delayed trip reference signal, and generating a trip signal when said delayed bandwidth limited di/dt signal exceeds said delayed trip reference signal.

Claim 15

Dependent Claim 61 words

The circuit breaker of claim 11 including filter means filtering said bandwidth limited di/dt signal used by said delay means in generating said delayed bandwidth limited di/dt signal, said filter means being selected to provide a selected relative sensitivity of said additional comparison means in generating a trip signal in response to persistent overcurrent fault currents and sputtering arc fault currents.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-06-28	1996-12-28	1997-06-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-06-28	2000-12-28	2001-06-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-06-28	2004-12-28	2005-06-29	$7700.00	Window Closed / Lapsed

Electronic circuit breaker with protection against sputtering arc faults and ground faults

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