Automated ground fault interrupt tester

Patent metadata

Field	Value
Publication number	US-10230232-B2
Application number	US-201615271719-A
Country	US
Kind code	B2
Filing date	Sep 21, 2016
Priority date	Sep 28, 2015
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A system includes a hot wire and a neutral wire configured to establish a closed circuit between a power source and a load. The system further includes first and second transformers as well as a sensor. The first current transformer is coupled to the hot wire and is configured to introduce a first test current, with a first polarity, into the hot wire. The second current transformer is coupled to the neutral wire and configured to substantially simultaneously introduce a second test current into the neutral wire. The second test current has the same polarity as the first test current. The sensor is configured to sense an asymmetry between the first and second test currents and is further configured to cause interruption of the closed circuit upon sensing the asymmetry.

First claim

What is claimed:

1. A system comprising:
a hot wire and a neutral wire, the hot wire and the neutral wire configured to establish a closed circuit between a power source and a load;
a first current transformer coupled to the hot wire and configured to introduce a first test current with a first polarity into the hot wire;
a second current transformer coupled to the neutral wire and configured to substantially simultaneously introduce a second test current, having the same polarity as the first test current, into the neutral wire
a sensor configured to sense an asymmetry between the first and second test currents and configured to cause interruption of the closed circuit upon sensing the asymmetry.

2. The system of claim 1 , wherein the hot wire, neutral wire, first and second transformers, and sensor are contained within a physical-interface-free enclosure.

3. The system of claim 1 , wherein the first and second current transformers are activated to introduce the first and second test currents, respectively, by a processor.

4. The system of claim 3 , wherein communication is established with the processor via a user interface.

5. The system of claim 4 , wherein the user interface enables a user to select from a plurality of closed circuits into which first and second test currents will be introduced.

6. The system of claim 1 , wherein the first and second test currents are in the exceed 6 mA.

7. The system of claim 1 , wherein the sensor comprises a sensing coil.

8. A method comprising:
introducing a first test current into a hot wire of a closed circuit, the hot wire coupled between a power source and a load;
introducing a second test current into a neutral wire of the closed circuit, the neutral wire coupled between the power source and the load, wherein the second test current is introduced at substantially the same time as the first test current and wherein the first and second test currents have the same polarity;
sensing an asymmetry between the first and second test currents; and
opening the closed circuit in response to sensing the asymmetry between the first and second test currents.

9. The method of claim 8 , wherein the first test current is introduced by a first current transformer electrically coupled to the hot wire.

10. The method of claim 9 , wherein the second test current is introduced by a second current transformer electrically coupled to the neutral wire.

11. The method of claim 8 , further comprising initiating the introduction of the first and second test currents through a user interface.

12. The method of claim 8 , wherein the first and second test currents exceed 6 mA.

13. The method of claim 8 , wherein the sensing is performed by a sensor coil.

14. The method of claim 8 , further comprising re-establishing the closed circuit after opening the closed circuit.

15. A system comprising:
a hot wire and a neutral wire, the hot wire and the neutral wire configured to establish a closed circuit between a power source and a load;
a ground fault interrupt circuit having a sensor configured to continuously monitor the currents flowing in the hot wire and the neutral wire, the ground fault interrupt circuit configured to open the closed circuit if the current in the hot and neutral wires are not substantially equal in magnitude,
a first current transformer coupled to the hot wire and configured to introduce a first test current with a first polarity into the hot wire;
a second current transformer coupled to the neutral wire and configured to substantially simultaneously introduce a second test current, having the same polarity as the first test current, into the neutral wire
wherein the sensor of the ground fault interrupt circuit is additional configured to detect an asymmetry in the waveforms of the first and second test currents, and wherein the ground fault interrupt circuit is additionally configured to open the closed circuit upon detection of the asymmetry.

16. The system of claim 15 , wherein the sensor comprises a sensing coil.

17. The system of claim 15 , wherein the first and second test currents exceed 6 mA.

18. The system of claim 15 , wherein the first and second current transformers are activated to introduce the first and second test currents, respectively, by a processor.

19. The system of claim 18 , wherein communication is established with the processor via a wireless user interface.

20. The system of claim 19 , wherein the wireless user interface enables a user to select from a plurality of closed circuit into which first and second test currents will be introduced.

Assignees

• Cooper Technologies Co
• Eaton Intelligent Power Ltd

Inventors

• Freer Benjamin Avery
• Iannce Stephan P
• Manahan Joseph Michael

Classifications

• H02H3/17

  by means of an auxiliary voltage injected into the installation to be protected {(using summation current transformers H02H3/33)} · CPC title

• G01R31/3277

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

• H02H3/335

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

• H02H3/162 Primary

  for AC systems · CPC title

• G01R31/025

  Physics · mapped topic