SELF-TESTING AUTO MONITOR GROUND FAULT CIRCUIT INTERRUPTER (GFCI) WITHPOWER DENIAL

• US 20140347768A1
• Filed: 03/11/2014
• Published: 11/27/2014
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: Hubbell, Inc.
• Original Assignee: Hubbell, Inc.
• Inventors: Batko, Thomas James, DeBartolo, Joseph Vincent
• Granted Patent: US 9,595,824 B2
• Time in Patent Office: Days
• US Class Current: 361/42
• CPC Class Codes: G01R 31/2827 Testing of electronic protection circuits testing switches G01R31/327; checking alarm systems G08B29/00; self test of summation current transformers H02H3/335
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H01H 2071/044 Monitoring, detection or measuring systems to establish the end of life of the switching device, can also contain other on-line monitoring systems, e.g. for detecting mechanical failures
• CPC Class Codes: H01H 2300/052 Controlling, signalling or testing correct functioning of a switch see also H01H2300/056 - H01H2300/066 and H01H11/0062
• CPC Class Codes: H01H 71/04 Means for indicating condition of the switching device by means of an auxiliary contact H01H71/46
• CPC Class Codes: H01H 83/04 with testing means for indicating the ability of the switch or relay to function properly
• CPC Class Codes: H02H 3/044 Checking correct functioning of protective arrangements, e.g. by simulating a fault for differential current circuit breakers H02H3/335
• CPC Class Codes: H02H 3/162 for ac systems
• CPC Class Codes: H02H 3/335 the main function being self testing of the device

Abstract

A self-testing fault detector having a line side and a load side and a conductive path there between is provided. The self-testing fault detector includes an auto-monitoring circuit electrically coupled to a fault detection circuit and an interrupting device and it continuously monitors one or more signals to determine an operating state of the fault detector. At least one of the monitored signals includes a fault detection signal, wherein if said automonitoring circuit determines that the fault detection circuit is not properly driving the interrupting device, the automonitoring device converts an input-output port receiving the fault detection signal from an input to an output and drives the interrupting device into a tripped condition using the input-output port.

Claims

1. A circuit interrupting device comprising:

one or more line terminals for connecting to an external power supply;

one or more load terminals for connecting to an external load;

an interrupting device connected to said line terminals and said load terminals and electrically connecting said line terminals to said load terminals when said circuit interrupting device is in a reset condition and disconnecting said line terminals from said load terminals 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 said fault detection signal, wherein if said automonitoring circuit determines that said fault detection circuit is not properly driving said interrupting device, said automonitoring device declares an end-of-life condition and converts an input-output port receiving said fault detection signal from an input to an output and drives said interrupting device into said tripped condition using said input-output port.

2. The circuit interrupting device recited in claim 1, wherein said automonitoring circuit prevents said interrupting device from being put into said reset state by providing a reset prevention signal from said input-output port.

3. The circuit interrupting device recited in claim 2, wherein said automonitoring circuit confirms said end-of-life condition during a time period when said reset prevention signal is being provided from said input-output port and, if said end-of-life condition remains, said automonitoring circuit continues to provide said reset prevention signal from said input-output port, and if said end-of-life condition does not remain, said automonitoring circuit ceases to provide said reset prevention signal from said input-output port.

4. The circuit interrupting device recited in claim 3, wherein said circuit interrupting device is placed is said reset condition after said automonitoring circuit confirms said end-of-life condition and after said automonitoring circuit ceases to provide said reset prevention signal from said input-output port.

5. A circuit interrupting device comprising:

one or more line terminals for connecting to an external power supply;

one or more load terminals for connecting to an external load;

an interrupting device connected to said line terminals and said load terminals and electrically connecting said line terminals to said load terminals when said circuit interrupting device is in a reset condition and disconnecting said line terminals from said load terminals 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 said fault detection signal and if said automonitoring circuit determines that said circuit interrupting device has reached its end-of-life and it is determined that contacts of said interrupting device have not failed, then a signal is driven to a first level to actuate a switch and open the contacts.

6. The circuit interrupting device claimed in claim 5, wherein said automonitoring circuit determines whether said contacts have failed by determining if the contacts are stuck together.

7. The circuit interrupting device claimed in claim 5, wherein said signal driven to actuate said switch to open the contacts is driven for at least 20 milliseconds.

8. The circuit interrupting device claimed in claim 5, further comprising at least one of actuating a visual indicator and actuating an audio indicator.

9. The circuit interrupting device claimed in claim 8, wherein said visual indicator includes a light emitting diode (LED).

10. The circuit interrupting device claimed in claim 5, wherein said signal driven to actuate said switch is driven to a second level to inhibit said circuit interrupting device from resetting.

11. A circuit interrupting device comprising:

one or more line terminals for connecting to an external power supply;

one or more load terminals for connecting to an external load;

an interrupter for electrically connecting said line terminals to said load terminals in a reset condition and electrically isolating said line terminals from said load terminals in a tripped condition;

an auto-monitoring circuit configured to automatically perform a self-test routine based on a predetermined schedule and determine whether said circuit interrupting device has reached the end of its useful life, wherein said determination is based at least in part on a result from said self-test routine,

wherein, when said auto-monitoring circuit determines that said circuit interrupting device has reached the end of its useful life, a driver signal is driven to a first level for a first length of time to actuate said interrupter to said tripped condition.

12. The circuit interrupting device claimed in claim 11, wherein said external power supply includes an AC source providing said circuit interrupting device with an AC power signal having a first number of cycles per second and said first length of time is greater than a duration of one of said cycles.

13. The circuit interrupting device claimed in claim 12, wherein said AC power signal is a 60 hertz signal having 60 cycles per second and said first length of time is greater than 16.667 milliseconds.

14. The circuit interrupting device claimed in claim 11, wherein said automonitoring circuit includes a microcontroller having one or more input/output (I/O) ports that can be configured by said automonitoring circuit to be either an input or an output, and when said auto-monitoring circuit determines that said circuit interrupting device has reached the end of its useful life at least one of said I/O ports is configured to be an output.

15. The circuit interrupting device claimed in claim 14, wherein said driver signal is output on said configured output port.

16. The circuit interrupting device claimed in claim 15, wherein said configured output port is changed to an output port from an input port, and said input port is configured to receive analog signals that are converted to digital signals within said microcontroller.