CIRCUIT INTERRUPTER WITH CONTINUOUS SELF-TESTING FEATURE

• US 20100073002A1
• Filed: 09/23/2008
• Published: 03/25/2010
• Est. Priority Date: 09/23/2008
• Status: Active Grant

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Bradley, Roger M., Chan, David, Porter, James A.
• Granted Patent: US 8,183,869 B2
• Time in Patent Office: Days
• US Class Current: 324/424
• CPC Class Codes: G01R 31/3272 Apparatus, systems or circuits therefor G01R31/3275 takes precedence
• CPC Class Codes: H01H 83/04 with testing means for indicating the ability of the switch or relay to function properly
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A circuit interrupter includes a current transformer, phase conductor and neutral conductor. The phase conductor and the neutral conductor are each configured to pass through the transformer from line side to load side that are defined by the current transformer. The circuit interrupter generates a continuous test current by continuous current imbalance established between the load side of the phase conductor and the line side of the neutral conductor, or between the line side of the phase conductor and the load side of the neutral conductor. A continuous test conductor may be coupled correspondingly to establish the current imbalance. Alternatively, an integrated circuit coupled correspondingly receives power and is energized by a quiescent current thereby. The current imbalance is established by the quiescent current. The current transformer detects the quiescent current as the continuous test current. Corresponding methods are also disclosed.

Claims

1. A circuit interrupter comprising:

a circuit interrupting actuation circuit; and

a fault current test circuit disposed and electrically coupled to the circuit interrupting actuation circuit to test at least partially the operability of the circuit interrupting actuation circuit, the test circuit disposed and configured to receive power from a power source,

wherein when the fault current test circuit is receiving power from the power source, the test circuit continuously tests at least partially the operability of the circuit interrupting circuit.

2. The circuit interrupter according to claim 1, wherein the circuit interrupter is selected from the group consisting of a (a) a ground fault circuit interrupter (GFCI);

(b) arc fault circuit interrupter (ACFI);

(c) immersion detection circuit interrupter (IDCI);

(d) appliance leakage circuit interrupter (ALCI);

(e) circuit breaker;

(f) contactor;

(g) latching relay; and

(h) solenoid mechanism.

3. The circuit interrupter according to claim 2,

wherein the circuit interrupter is a ground fault circuit interrupter,

wherein the circuit interrupting actuation circuit comprises:

a current transformer;

a phase conductor; and

a neutral conductor,

the phase and neutral conductors each having a line side and a load side,

the phase conductor and the neutral conductor being each configured to pass through the transformer from the line side to the load side,

the line side and the load side of the phase and neutral conductors being defined by the current transformer, and

wherein when the fault current test circuit is receiving power from the power source, the test circuit continuously tests at least partially the operability of the circuit interrupting circuit via the fault current test circuit being disposed and electrically coupled to allow passage of a continuous test current by a continuous current imbalance one of (a) between the load side of the phase conductor and the line side of the neutral conductor, and (b) between the line side of the phase conductor and the load side of the neutral conductor.

4. The circuit interrupter according to claim 3, wherein the ground fault circuit interrupter further comprises:

a current transformer,

the phase conductor and the neutral conductor being each configured to pass through the transformer from the line side to the load side,

the line side and the load side of the phase and neutral conductors being defined by the current transformer.

5. The circuit interrupter according to claim 4,

wherein the ground fault circuit interrupter is configured to allow passage of the continuous test fault current by being configured to allow passage of the continuous current imbalance via a continuous test conductor electrically coupling one of (a) the load side of the phase conductor and the line side of the neutral conductor;

and (b) the line side of the phase conductor and the load side of the neutral conductor, respectively,

the ground fault circuit interrupter further comprising a fault generator circuit electrically coupled in the continuous test conductor and configured to generate the continuous test fault current therein.

6. The circuit interrupter according to claim 5, further comprising:

an integrated circuit,

wherein the current transformer is electrically coupled to the integrated circuit.

7. The circuit interrupter according to claim 6, wherein the integrated circuit is configured to detect the continuous test fault current.

8. The circuit interrupter according to claim 6, wherein the integrated circuit is configured to substantially null the continuous test fault current.

9. The circuit interrupter according to claim 7,

wherein the current transformer is configured to detect the current imbalance;

and

wherein the integrated circuit is configured to initiate a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor, and (2) the load side of the neutral conductor from the line side of the neutral conductor, if the current imbalance detected by the current transformer is greater than the sum of a predetermined magnitude and the continuous test fault current.

10. The circuit interrupter according to claim 7, further comprising an autogain circuit electrically coupled to the current transformer and to the integrated circuit, wherein the autogain circuit is configured to substantially null the continuous test fault current detected by the integrated circuit.

11. The circuit interrupter according to claim 5, wherein the continuous test conductor further comprises an impedance load electrically coupled therein and configured wherein the magnitude of the continuous test current is proportional to the magnitude of the impedance load.

12. The circuit interrupter according to claim 11, wherein the impedance load is at least one of (a) a resistive load;

(b) a capacitive load; and

(c) an inductive load.

13. The circuit interrupter according to claim 11, wherein the continuous test conductor further comprises a fault detection circuit electrically coupled therein and configured to detect the continuous fault current.

14. The circuit interrupter according to claim 4,

wherein the ground fault circuit interrupter further comprises:

an integrated circuit configured and disposed to receive power one of (a) across the load side of the phase conductor and the line side of the neutral conductor, and (b) across the line side of the phase conductor and the load side of the neutral conductor, respectively, said integrated circuit being energized by a quiescent current thereby, and

wherein the current imbalance is established by the quiescent current, the current transformer being configured and disposed to detect the quiescent current as the continuous test current.

15. The circuit interrupter according to claim 14, wherein the ground fault circuit interrupter further comprises:

a rectifier electrically coupled to the integrated circuit,

wherein the quiescent current is established by the rectifier being electrically coupled via a conductor one of (a) between the line side of the phase conductor and the load side of the neutral conductor; and

(b) between the load side of the phase conductor and the line side of the neutral conductor.

16. The circuit interrupter according to claim 14,

wherein the current transformer is configured to detect the current imbalance, and

wherein the integrated circuit is configured and disposed to initiate a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor and (2) the load side of the neutral conductor from the line side of the neutral conductor, said trip signal being initiated by the integrated circuit if the current imbalance detected by the current transformer is greater than the sum of a predetermined magnitude and the continuous test fault current.

17. The circuit interrupter according to claim 14, further comprising:

an autogain controller electrically coupled to the integrated circuit wherein the autogain controller is configured to substantially null the current imbalance received as the quiescent current by the integrated circuit.

18. A method of testing a circuit interrupter comprising the steps of:

providing a circuit interrupter;

coupling electrical power to the circuit interrupter; and

continuously at least partially testing operability of the circuit interrupter.

19. The method of testing a circuit interrupter according to claim 18,

wherein the circuit interrupter comprises:

a circuit interrupting actuation circuit; and

a fault current test circuit disposed and electrically coupled to the circuit interrupting actuation circuit and configured to test at least partially the operability of the circuit interrupting actuation circuit, and

wherein the steps of connecting electrical power to the circuit interrupter and continuously at least partially testing the operability of the circuit interrupter comprise;

connecting electrical power to the fault current test circuit; and

continuously at least partially testing the operability of the circuit interrupting actuation circuit.

20. The method of testing a circuit interrupter according to claim 18,

wherein the circuit interrupter is one of the group consisting of a (a) a ground fault circuit interrupter (GFCI);

(b) arc fault circuit interrupter (ACFI);

(c) immersion detection circuit interrupter (IDCI);

(d) appliance leakage circuit interrupter (ALCI);

(e) circuit breaker;

(f) contactor;

(g) latching relay; and

(h) solenoid mechanism.

21. The method of testing a circuit interrupter according to claim 20,

wherein the circuit interrupter is a ground fault circuit interrupter,

wherein the circuit interrupting actuation circuit comprises:

a current transformer;

a phase conductor; and

a neutral conductor,

the phase and neutral conductors each having a line side and a load side,

the phase conductor and the neutral conductor being each configured to pass through the transformer from the line side to the load side,

the line side and the load side of the phase and neutral conductors being defined by the current transformer, and

the method further comprising the steps of;

coupling electrical power to the fault current test circuit; and

continuously at least partially testing the operability of the circuit interrupting circuit by establishing a continuous current imbalance one of;

(a) between the load side of the phase conductor and the line side of the neutral conductor; and

(b) between the line side of the phase conductor and the load side of the neutral conductor.

22. The method of testing a circuit interrupter according to claim 21, further comprising the step of:

electrically coupling a continuous test conductor one of (a) between the load side of the phase conductor and the line side of the neutral conductor; and

(b) between the line side of the phase conductor and the load side of the neutral conductor, respectively,

wherein the ground fault circuit interrupter is configured to allow passage of the continuous current imbalance via a continuous test conductor electrically coupling one of (a) the load side of the phase conductor and the line side of the neutral conductor; and

(b) the line side of the phase conductor and the load side of the neutral conductor, respectively,

providing a fault generator circuit electrically coupled in the continuous test conductor; and

generating the continuous test fault current in the continuous test conductor via the fault generator circuit.

23. The method of testing a circuit interrupter according to claim 22, further comprising the steps of:

providing a current transformer; and

configuring the phase conductor and the neutral conductor to pass through the current transformer from the line side to the load side,

the line side and the load side of the phase and neutral conductors being defined by the current transformer.

24. The method of testing a circuit interrupter according to claim 23, further comprising the steps of:

electrically coupling an integrated circuit to the current transformer; and

detecting the continuous test fault current via the integrated circuit.

25. The method of testing a circuit interrupter according to claim 24, further comprising the step of:

substantially nulling the continuous test fault current.

26. The method of testing a circuit interrupter according to claim 24, further comprising the steps of:

detecting the current imbalance via the current transformer; and

initiating a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor, and (2) the load side of the neutral conductor from the line side of the neutral conductor, if the current imbalance detected by the current transformer is greater than the sum of a predetermined magnitude and the continuous test fault current.

27. The method of testing a circuit interrupter according to claim 24, further comprising the steps of:

providing an autogain circuit electrically coupled to the current transformer and to the integrated circuit; and

substantially nulling the continuous test fault current detected by the integrated circuit via the autogain circuit.

28. The method of testing a circuit interrupter according to claim 22, further comprising the step of:

electrically coupling an impedance load in the continuous test conductor, wherein the magnitude of the continuous test current is proportional to the magnitude of the impedance load.

29. The method of testing a circuit interrupter according to claim 28 wherein the impedance load is at least one of (a) a resistive load;

(b) a capacitive load; and

(c) an inductive load.

30. The method of testing a circuit interrupter according to claim 28, further comprising the steps of:

electrically coupling a fault detection circuit in the continuous test conductor; and

detecting the continuous fault current.

31. The method of testing a circuit interrupter according to claim 21, further comprising the steps of:

providing an integrated circuit receiving power one of (a) across the load side of the phase conductor and the line side of the neutral conductor, and (b) across the line side of the phase conductor and the load side of the neutral conductor, said integrated circuit being energized by a quiescent current thereby;

establishing the current imbalance by the quiescent current; and

detecting, via the current transformer, the quiescent current as the continuous test current.

32. The method of testing a circuit interrupter according to claim 31, further comprising the steps of:

electrically coupling a rectifier to the integrated circuit; and

electrically coupling a conductor one of (a) between the line side of the phase conductor and the load side of the neutral conductor; and

(b) between the load side of the phase conductor and the line side of the neutral conductor to establish the quiescent current thereby.

33. The method of testing a circuit interrupter according to claim 31, further comprising the steps of:

configuring the current transformer to detect the current imbalance; and

initiating a trip signal by the integrated circuit if the current imbalance detected by the current transformer is greater than the sum of a predetermined magnitude and the continuous test fault current.

34. The method of testing a circuit interrupter according to claim 33,

wherein the integrated circuit is configured and disposed to initiate a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor and (2) the load side of the neutral conductor from the line side of the neutral conductor,

35. The method of testing a circuit interrupter according to claim 31, further comprising the steps of:

electrically coupling an autogain controller to the integrated circuit; and

substantially nulling, via the autogain controller, the current imbalance received as the quiescent current by the integrated circuit.

36. A method of manufacturing a circuit interrupter comprising the steps of:

providing a circuit interrupter;

configuring the circuit interrupter to receive electrical power from a power source; and

configuring the circuit interrupter with circuitry to enable at least partial continuous testing of the circuit interrupter when electrical power is received by the circuit interrupter.

37. The method of manufacturing a circuit interrupter according to claim 36, wherein the circuit interrupter is one of the group consisting of a (a) a ground fault circuit interrupter (GFCI);

(b) arc fault circuit interrupter (ACFI);

(c) immersion detection circuit interrupter (IDCI);

(d) appliance leakage circuit interrupter (ALCI);

(e) circuit breaker;

(f) contactor;

(g) latching relay; and

(h) solenoid mechanism.

38. The method of manufacturing a circuit interrupter according to claim 37

wherein the circuit interrupter is a ground fault circuit interrupter and the step of configuring the circuit interrupter with circuitry to enable at least partial continuous testing of the circuit interrupter when electrical power is received by the circuit interrupter is performed by configuring the ground fault circuit interrupter with circuitry allowing passage of a continuous test current therein to enable at least partial continuous testing of the ground fault circuit interrupter when electrical power is received by the circuit interrupter.

39. The method of manufacturing a circuit interrupter according to claim 38,

wherein the circuitry of the ground fault circuit interrupter comprises:

a phase conductor having a line side and a load side; and

a neutral conductor having a line side and a load side, and

wherein the step of configuring the ground fault circuit interrupter with circuitry allowing passage of a continuous test current therein to enable the at least partial continuous testing is performed by;

configuring the ground fault circuit interrupter to allow passage of the continuous test current as a continuous current imbalance one of (a) between the load side of the phase conductor and the line side of the neutral conductor; and

(b) between the line side of the phase conductor and the load side of the neutral conductor.

40. The method of manufacturing a circuit interrupter according to claim 39, further comprising the steps of:

providing a current transformer; and

configuring the phase conductor and the neutral conductor each to pass through the transformer from the line side to the load side,

the line side and the load side of the phase and neutral conductors being defined by the current transformer.

41. The method of manufacturing a circuit interrupter according to claim 40,

wherein the step of configuring the ground fault circuit interrupter to allow passage of the continuous test current as a continuous current imbalance is performed by electrically coupling a continuous test conductor one of (a) between the load side of the phase conductor and the line side of the neutral conductor;

and (b) between the line side of the phase conductor and the load side of the neutral conductor, respectively, establishing the continuous test fault current in the continuous test conductor thereby.

42. The method of manufacturing a circuit interrupter according to claim 41, further comprising the step of:

configuring the ground fault circuit interrupter to initiate a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor, and (2) the load side of the neutral conductor from the line side of the neutral conductor if the current imbalance is greater than the sum of a predetermined magnitude and the continuous test fault current.

43. The method of manufacturing a circuit interrupter according to claim 38, further comprising the step of:

configuring the ground fault circuit interrupter to substantially null the continuous test fault current.

44. The method of manufacturing a circuit interrupter according to claim 40, further comprising the steps of:

providing an integrated circuit configured and disposed to receive power one of (a) across the load side of the phase conductor and the line side of the neutral conductor, and (b) across the line side of the phase conductor and the load side of the neutral conductor, respectively, said integrated circuit being energized by a quiescent current thereby,

configuring the ground fault circuit interrupter wherein the current imbalance is the quiescent current; and

configuring and electrically coupling the current transformer to detect the quiescent current as the continuous test current.

45. The method of manufacturing a circuit interrupter according to claim 40, further comprising the steps of:

providing a rectifier electrically coupled to the integrated circuit; and

electrically coupling the rectifier via a conductor one of;

(a) between the line side of the phase conductor and the load side of the neutral conductor; and

(b) between the load side of the phase conductor and the line side of the neutral conductor, the quiescent current being established thereby.

46. The method of manufacturing a circuit interrupter according to claim 45, further comprising the step of:

configuring the ground fault circuit interrupter to initiate a trip signal to decouple at least one of (1) the load side of the phase conductor from the line side of the phase conductor, and (2) the load side of the neutral conductor from the line side of the neutral conductor if the current imbalance is greater than the sum of a predetermined magnitude and the continuous test fault current.

47. The method of manufacturing a circuit interrupter according to claim 44, further comprising the step of:

providing an autogain controller; and

electrically coupling the autogain controller to the integrated circuit wherein the autogain controller substantially nulls the current imbalance received as the quiescent current by the integrated circuit.