GFCI test monitor circuit
First Claim
1. A circuit interrupting device comprising:
- one or more line conductors for electrically connecting to an external power supply;
one or more load conductors for electrically connecting to an external load;
an interrupting device connected to said line conductors and said load conductors and electrically connecting said line conductors to said load conductors when said circuit interrupting device is in a reset condition and disconnecting said line conductors from said load conductors when said circuit interrupting device is in a tripped condition;
a fault detection circuit that detects a fault condition in said circuit interrupting device and generates a fault detection signal when said fault condition is detected, wherein said fault detection signal is provided to said interrupting device to place said circuit interrupting device in said tripped condition;
an auto-monitoring circuit electrically coupled to said fault detection circuit and said interrupting device and continuously monitoring one or more signals to determine an operating state of said circuit interrupting device, wherein at least one of said monitored signals includes a first auto-monitoring input signal the value of which is at least partially determined by a value of a pre-trigger signal generated by said fault detection circuit, wherein said pre-trigger signal does not activate said interrupting device to place said circuit interrupting device in said tripped condition.
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Accused Products
Abstract
A circuit interrupting device having an auto-monitoring circuit for periodically testing various functions and structures of the device. The auto-monitoring circuit initiates an auto-monitoring routine which, among other things, generates a self-test fault condition and determines whether the detection mechanisms within the device properly detect the self-test fault. Processing an early detection signal determines whether the self-test fault was properly detected without interfering with the normal operation of the detection circuitry and without causing a false trip within the device. Additional functionality of the auto-monitoring circuit permits automatic verification that the device is properly wired, that is, not miswired, and determines whether the device has reached the end of its useful life.
85 Citations
19 Claims
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1. A circuit interrupting device comprising:
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one or more line conductors for electrically connecting to an external power supply; one or more load conductors for electrically connecting to an external load; an interrupting device connected to said line conductors and said load conductors and electrically connecting said line conductors to said load conductors when said circuit interrupting device is in a reset condition and disconnecting said line conductors from said load conductors when said circuit interrupting device is in a tripped condition; a fault detection circuit that detects a fault condition in said circuit interrupting device and generates a fault detection signal when said fault condition is detected, wherein said fault detection signal is provided to said interrupting device to place said circuit interrupting device in said tripped condition; an auto-monitoring circuit electrically coupled to said fault detection circuit and said interrupting device and continuously monitoring one or more signals to determine an operating state of said circuit interrupting device, wherein at least one of said monitored signals includes a first auto-monitoring input signal the value of which is at least partially determined by a value of a pre-trigger signal generated by said fault detection circuit, wherein said pre-trigger signal does not activate said interrupting device to place said circuit interrupting device in said tripped condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A wiring device comprising:
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a fault detection circuit configured to detect one or more fault conditions in said wiring device and generate a fault detection signal when said fault condition meets a first predetermined criteria and a pre-trigger signal when said fault condition meets a second predetermined criteria, wherein said one or more fault conditions includes a self-test fault condition; a programmable circuit device programmed to execute an auto-monitoring routine that includes the following steps; generating a self-test fault signal at a first output port of said programmable circuit device, wherein said self-test fault signal generates a self-test fault condition in said wiring device; input said pre-trigger signal to said programmable circuit device at a first input port; determining the value of said pre-trigger signal; processing said value of said pre-trigger signal; determining whether said fault detection circuit successfully detected said self-test fault based on said processed value of said pre-trigger signal; incrementing a failure count if it is determined that said fault detection circuit failed to successfully detect said self-test fault; and resetting said failure count if it is determined that said fault detection circuit did successfully detect said self-test fault. - View Dependent Claims (14, 15)
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16. A wiring device comprising:
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a fault detection circuit configured to detect one or more fault conditions in said wiring device and generate a fault detection signal when said fault condition meets a first predetermined criteria and a pre-trigger signal when said fault condition meets a second predetermined criteria, wherein said one or more fault conditions includes a self-test fault condition, a real fault condition and a simulated fault condition; two switching devices each electrically coupled to one of a first and second coil of a dual coil solenoid, wherein said first and second coils conduct electric current when their respective switching devices are activated; a third switching device electrically coupled to said first and second coils of said dual coil solenoid, wherein said first and second coils conduct electric current when said third switching device is activated; a programmable circuit device programmed to execute an auto-monitoring routine that includes the following steps, periodically generating a self-test fault signal at a first output port of said programmable circuit device, wherein said self-test fault signal generates a self-test fault condition in said wiring device; input said pre-trigger signal to said programmable circuit device at a first input port; incrementing a counter if the value of said pre-trigger signal is greater than or equal to a first threshold; resetting said counter if the value of said pre-trigger signal is less than said first threshold; activating one or more of said first and second switching devices if said counter reaches a predetermined threshold value. - View Dependent Claims (17, 18)
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19. A method of operating a wiring device comprising the steps of:
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periodically generating a self-test fault signal; detecting said self-test fault signal; generating a pre-trigger signal when said self-test fault signal is detected; incrementing a counter if the value of said pre-trigger signal is greater than or equal to a first threshold; resetting said counter if the value of said pre-trigger signal is less than said first threshold; determining that either a real fault condition or a simulated fault condition has occurred if the value of said pre-trigger signal is greater than a second threshold less than said first threshold; ceasing generation of said self-test fault signal if it is determined that either a real fault condition or a simulated fault condition has occurred; continuing generation of said self-test fault signal if it is determined that either a real fault condition or a simulated fault condition has not occurred; and generating a fault detection signal if it is determined that a real fault condition has occurred.
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Specification