Controllable test-pulse width and position for self-test ground fault circuit interrupter

Patent metadata

Field	Value
Publication number	US-10461520-B2
Application number	US-201715480653-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Aug 27, 2013
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

An electrical wiring device including a fault detection circuit and a test fault circuit. The fault detection circuit is configured to detect real, simulated and test fault conditions. The test fault circuit is configured to generate one or more test pulses that cause said test fault condition. Wherein said one or more test pulses are generated to occur outside of an active region of said fault detection circuit, and wherein the one or more test pulses do not affect a leakage current.

First claim

What is claimed is:

1. An electrical wiring device comprising:
a fault detection circuit configured to detect real, simulated and test fault conditions; and
a test fault circuit configured to generate one or more test pulses that cause said test fault condition, wherein said one or more test pulses are generated to occur approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

2. The electrical wiring device recited in claim 1 , wherein said one or more test pulses each has a pulsewidth that is less than 1 msec.

3. The electrical wiring device recited in claim 1 , wherein the leakage current is present in the active region.

4. The electrical wiring device recited in claim 1 , wherein the one or more test pulses do not affect the leakage current by not adding to or subtracting from the leakage current.

5. The electrical wiring device recited in claim 1 , wherein said one or more test pulses occur approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

6. The electrical wiring device recited in claim 1 , wherein said one or more test pulses occur only within the last quarter of a positive half-cycle of AC power.

7. The electrical wiring device recited in claim 1 , wherein said one or more test pulses are generated by a programmable device.

8. 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; and
a test fault circuit configured to generate one or more test pulses that cause said test fault condition, wherein said one or more test pulses are generated to occur approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

9. The circuit interrupting device recited in claim 8 , wherein said fault detection circuit includes a sense transformer through which said line conductors are disposed, said sense transformer generating an induced fault detection signal when a net current exceeds a predetermined threshold.

10. The circuit interrupting device recited in claim 9 , wherein said self-test circuit includes a self-test conductor disposed through said sense transformer and separate from said line conductors and said net current is placed on said self-test conductor when said self-test circuit is controlled to generate said self-test signal.

11. The circuit interrupting device recited in claim 8 , wherein the one or more test pulses do not affect the leakage current by not adding to or subtracting from the leakage current.

12. The circuit interrupting device recited in claim 8 , wherein said one or more test pulses occur approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

13. The circuit interrupting device recited in claim 8 , wherein said one or more test pulses occur only within the last quarter of a positive half-cycle of AC power.

14. The circuit interrupting device recited in claim 8 , wherein said one or more test pulses each has a pulse width that is less than 1 msec.

15. The circuit interrupting device recited in claim 8 , wherein a leakage current is present in the active region.

16. An electrical wiring device comprising:
a fault detection circuit configured to detect real, simulated, and test fault conditions;
a test fault circuit configured to generate one or more test pulses that cause said test fault condition, wherein said one or more test pulses are generated to occur outside of an active region of said fault detection circuit,
wherein said test fault circuit includes a programmable device programmed to generate said one or more test pulses, wherein the one or more test pulses are generated approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

17. The electrical wiring device recited in claim 16 , wherein the one or more test pulses do not affect the leakage current by not adding to or subtracting from the leakage current.

18. The electrical wiring device recited in claim 16 , wherein said one or more test pulses occur approximately five milliseconds after a leading edge of a positive half-cycle of AC power.

19. The electrical wiring device recited in claim 16 , wherein said one or more test pulses occur only within the last quarter of a positive half-cycle of AC power.

Assignees

• Hubbell Inc

Inventors

• Simonin Stephen

Classifications

• H02H3/335

  the main function being self testing of the device · CPC title

• H02H3/162 Primary

  for AC systems · CPC title

• G01R31/3277

  of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches · CPC title