Current fault detector and circuit interrupter and packaging thereof

• US 20030030954A1
• Filed: 07/19/2002
• Published: 02/13/2003
• Est. Priority Date: 02/01/2001
• Status: Active Grant

• Current Assignee: Hydro-Aire Aerospace Corporation (Crane Company)
• Original Assignee: Hydro-Aire Incorporated Subsidiary of Crane Company
• Inventors: King, Timothy E., Rusali, Rudy H., Bax, Ronald A.
• Granted Patent: US 7,016,171 B2
• Time in Patent Office: Days
• US Class Current: 361/87
• CPC Class Codes: H01H 83/226 with differential transformer
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02H 3/04 with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned watching of pilot wires H02H1/0084; protection of protective arrangements H02H7/008; indication of the state of electronic switches H03K17/18
• CPC Class Codes: H02H 3/105 responsive to excess current and fault current to earth
• CPC Class Codes: H02H 3/335 the main function being self testing of the device
• CPC Class Codes: H02H 3/347 using summation current transformers

Abstract

A power controller is positioned within a current path between the line side and the load side of an electrical circuit. The power controller closes the current path in the presence of a control supply and opens the current path in the absence of the control supply. A power supply electrically connected to the current path provides the control supply. A sensor system receives power from the power supply, monitors the current in the current path and outputs a sensor signal indicative of a current condition within the current path. A logic controller also receives power from the power supply, receives the sensor signal and removes the control supply from the power controller when the sensor signal does not satisfy an established criteria. The sensor system may include one or both of an imbalance sensor for monitoring the current balance among two or more electrical lines and over-current sensors for monitoring current in individual lines.

Claims

1. A device for interrupting a current path between the line side and the load side of an electrical circuit:

a power supply electrically connected to the current path;

a power controller positioned within the current path and adapted to close the current path in the presence of a control supply and open the current path in the absence of the control supply;

a sensor system adapted to receive power from the power supply, monitor the current in the current path and output a sensor signal indicative of a current condition within the current path; and

a logic controller adapted to receive power from the power supply, receive the sensor signal and remove the control supply from the power controller when the sensor signal does not satisfy an established criteria.

2. The device of claim 1 wherein the power supply is electrically connected to the line side of the current path.

3. The device of claim 1 wherein the control supply is provided by the power supply and the power supply is adapted to:

when the power controller is open and the sensor signal satisfies the established criteria, output a control supply having a first voltage for a first amount of time, the first voltage sufficient to cause the power controller to close the current path; and

after the first amount of time, output a control supply having a second voltage sufficient to hold the power controller in the closed position;

wherein the second voltage is less than the first voltage.

4. The device of claim 1 wherein the current path comprises three electrical lines, the sensor system comprises a single sensor associated with the electrical lines and the current condition comprises the current balance among the electrical lines.

5. The device of claim 1 wherein the current path comprises three electrical lines, the sensor system comprises three sensors, each associated with one of the electrical lines and the current condition comprises the current measurement in each electrical line.

6. The device of claim 1 wherein the current path comprises three electrical lines, the sensor system comprises four sensors, three sensors each associated with one of the electrical lines individually and one sensor associated with the three electrical lines collectively, and the current condition comprises the current balance among the electrical lines and the current measurement in each electrical line.

7. The device of claim 1 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the lines and the current condition comprises the current balance among the DC voltage line and the return line.

8. The device of claim 1 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the DC voltage line and the current condition comprises the current measurement in the DC voltage line.

9. The device of claim 1 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises two sensors, one sensor associated with the DC voltage line individually and one sensor associated with the DC voltage line and the return line collectively, and the current condition comprises the current balance among the DC voltage line and the return line and the current measurement in the DC voltage line.

10. The device of claim 1 wherein the sensors comprise any one of a Hall effect sensor, a current transformer and a giant magneto resistive sensor.

11. The device of claim 1 wherein the logic controller comprises electrical circuitry configured to compare the sensor signal to a preestablished threshold range and to output a fault signal when the sensor signal is not within the range.

12. The device of claim 11 wherein the sensor system comprises a sensor associated with at least two electrical lines, the sensor adapted to output a sensor signal indicative of the current balance among the electrical lines and the predetermined threshold range is between approximately −

1.5 A RMS and +1.5 A RMS.

13. The device of claim 11 wherein the load side of the electrical circuit is connected to an electrical load having an associated operating current, the sensor system comprises at least one sensor associated with one electrical line, the sensor adapted to output a signal indicative of the current passing through the electrical line and the predetermined threshold value is approximately 1.25 ×

the operating current.

14. The device of claim 11 wherein the load side of the electrical circuit is connected to an electrical load having an associated first operating current for a first amount of time and a second operating current for a second amount of time and the logic controller comprises circuitry adapted to set the predetermined threshold value at a first level during the first amount of time and a second level during the second amount of time.

15. The device of claim 11 wherein the first amount of time comprises the startup time associated with the electrical load and the second amount of time comprises time other than the startup time.

16. The device of claim 1 wherein the power controller comprises a DC relay.

17. The device of claim 1 wherein the power controller comprises a AC relay.

18. The device of claim 1 wherein the logic controller is further adapted to monitor the voltage level of the power provided to the sensor system by the power supply and ignore the sensor signal when the voltage level to the sensor system is less than a predetermined value.

19. The device of claim 1 wherein the logic controller is further adapted to monitor an external on/off power switch and remove the control supply from the power controller when either of the following conditions occur:

the sensor signal does not satisfy an established criteria, or the external power switch is off.

20. The device of claim 1 further comprising test circuitry adapted to cause the sensor system to output a sensor signal that does not satisfy the established criteria.

21. The device of claim 20 wherein the test circuitry comprises:

a coil having a plurality of turns wrapped around the sensor system, the coil having a first end and a second end; and

a test switch having an opened position and a closed position and adapted to, when in the closed position, establish a voltage potential across the first and second ends sufficient to cause the sensor system to output a sensor signal that does not satisfy the established criteria and, when in the opened position, remove the voltage potential across the first and second ends.

22. An integrated current fault detection/circuit breaker comprising:

a circuit breaker adapted to be positioned within a current path having a line side and a load side;

a power supply electrically connected to the current path;

a sensor system adapted to receive power from the power supply, monitor the current in the current path and output a sensor signal indicative of a current condition within the current path; and

a controller adapted to receive power from the power supply, receive the sensor signal and open the circuit breaker when the sensor signal does not satisfy an established criteria.

23. The device of claim 22 wherein the current path comprises three electrical lines, the sensor system comprises a single sensor associated with the electrical lines and the current condition comprises the current balance among the electrical lines.

24. The device of claim 22 wherein the current path comprises three electrical lines, the sensor system comprises three sensors, each associated with one of the electrical lines and the current condition comprises the current measurement in each electrical line.

25. The device of claim 22 wherein the current path comprises three electrical lines, the sensor system comprises four sensors, three sensors each associated with one of the electrical lines individually and one sensor associated with the three electrical lines collectively, and the current condition comprises the current balance among the electrical lines and the current measurement in each electrical line.

26. The device of claim 22 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the lines and the current condition comprises the current balance among the DC voltage line and the return line.

27. The device of claim 22 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the DC voltage line and the current condition comprises the current measurement in the DC voltage line.

28. The device of claim 22 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises two sensors, one sensor associated with the DC voltage line individually and one sensor associated with the DC voltage line and the return line collectively, and the current condition comprises the current balance among the DC voltage line and the return line and the current measurement in the DC voltage line.

29. A current fault protection device comprising:

a power controller adapted to be positioned within a current path having a line side and a load side, the power controller further adapted to switch the current path between open and closed positions in response to control signals;

a power supply electrically connected to the current path;

a sensor system adapted to receive power from the power supply, monitor the current in the current path and output a sensor signal indicative of a current condition within the current path; and

a logic controller adapted to receive power from the power supply, receive the sensor signal and output control signals the power controller to open the current path when the sensor signal does not satisfy an established criteria.

30. The device of claim 29 wherein the current path comprises three electrical lines, the sensor system comprises a single sensor associated with the electrical lines and the current condition comprises the current balance among the electrical lines.

31. The device of claim 29 wherein the current path comprises three electrical lines, the sensor system comprises three sensors, each associated with one of the electrical lines and the current condition comprises the current measurement in each electrical line.

32. The device of claim 29 wherein the current path comprises three electrical lines, the sensor system comprises four sensors, three sensors each associated with one of the electrical lines individually and one sensor associated with the three electrical lines collectively, and the current condition comprises the current balance among the electrical lines and the current measurement in each electrical line.

33. The device of claim 29 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the lines and the current condition comprises the current balance among the DC voltage line and the return line.

34. The device of claim 29 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises a single sensor associated with the DC voltage line and the current condition comprises the current measurement in the DC voltage line.

35. The device of claim 29 wherein the current path comprises a DC voltage line and a return line, the sensor system comprises two sensors, one sensor associated with the DC voltage line individually and one sensor associated with the DC voltage line and the return line collectively, and the current condition comprises the current balance among the DC voltage line and the return line and the current measurement in the DC voltage line.

36. A method of interrupting a current path between the line side and the load side of an electrical circuit having a power supply electrically connected thereto:

positioning a power controller in the current path, the power controller adapted to be in a closed position when provided with a control supply and in an open position otherwise;

monitoring the current in the current path and outputting a sensor signal indicative of a current condition within the current path using a sensor system; and

providing the control supply to the power controller only when the sensor signal satisfies an established criteria

37. The method of claim 36 wherein the sensor system is powered by the power supply.

38. The method of claim 36 wherein the control supply is provided by the power supply.

39. The method of claim 36 wherein the current path comprises three electrical lines and monitoring the current comprises:

associating a single current sensor with the three electrical lines; and

measuring the current balance among the electrical lines.

40. The method of claim 36 wherein the current path comprises three electrical lines and monitoring the current comprises:

associating a current sensor with each of the electrical lines; and

measuring the current in each electrical line.

41. The method of claim 36 wherein the current path comprises three electrical lines and monitoring comprises:

associating a single current sensor with the three electrical lines;

measuring the current balance among the electrical lines;

associating a current sensor with each of the electrical lines; and

measuring the current in each electrical line.

42. The method of claim 36 wherein the current path comprises a DC voltage line and a return line and monitoring the current comprises:

associating a single sensor with the two lines; and

measuring the current balance among the DC voltage line and the return line.

43. The method of claim 36 wherein the current path comprises a DC voltage line and a return line and monitoring the current comprises:

associating a single sensor with the DC voltage line; and

measuring the current in the DC voltage line.

44. The method of claim 36 wherein the current path comprises a DC voltage line and a return line and monitoring the current comprises:

associating a single sensor with the two lines;

measuring the current balance among the DC voltage line and the return line.

associating a single sensor with the DC voltage line; and

measuring the current in the DC voltage line.

45. The method of claim 36 wherein providing the control supply comprises:

when the power controller is in an opened position and the sensor signal satisfies the established criteria, outputting a control supply having a first voltage for a first amount of time, the first voltage sufficient to cause the power controller to switch to the closed position; and

after the first amount of time, outputting a control supply having a second voltage, less than the first voltage, sufficient to hold the power controller in the closed position.

46. The method of claim 36 furthering comprising:

monitoring the voltage level of the power provided to the sensor system by the power supply; and

ignoring the sensor signal when the voltage level to the sensor system is less than a predetermined value.

47. The method of claim 36 further comprising:

monitoring an external on/off power switch; and

removing the control supply from the power controller when either of the following conditions occur;

the sensor signal does not satisfy the established criteria, or the external power switch is off.

48. The method of claim 36 wherein the load side of the electrical circuit is connected to an electrical load having an associated first operating current for a first amount of time and a second operating current for a second amount of time and the method further comprises:

setting the established criteria to a first level during the first amount of time and a second level during the second amount of time.

49. A device for monitoring the current path through an electrical circuit having a line side and a load side and a power controller therebetween, the power controller adapted to close the current path in the presence of a control supply and open the current path in the absence of the control supply, the electrical circuit housed within a housing, said device comprising:

a power supply housed within the housing and electrically connected to the current path;

a sensor system housed within the housing and adapted to receive power from the power supply, monitor the current in the current path and output a sensor signal indicative of a current condition within the current path; and

a logic controller housed within the housing and adapted to receive power from the power supply, receive the sensor signal and remove the control supply from the power controller when the sensor signal does not satisfy an established criteria.

50. The device of claim 49 further comprising a flexible printed wiring board positioned around a portion of the power controller, wherein circuitry comprising at least one of the power supply, sensor system and logic controller are mounted on the board.

51. The device of claim 49 further comprising an light emitting diode interfacing with the logic controller, positioned on the outside of the housing and adapted to illuminate when the sensor signal does not satisfy the established criteria.

52. The device of claim 49 further comprising a mechanical indicator having first and second positions, interfacing with the logic controller and positioned on the outside of the housing and adapted to change positions when the sensor signal does not satisfy the established criteria.

53. A method of replacing an existing power controller positioned between the load side and line side of an electrical current path and housed within a housing having a specific form factor, said method comprising:

removing the existing power controller from the current path;

providing a device adapted to monitor a current condition through the current path and interrupt the current path when the current condition does not satisfy an established criteria, the device housed within a housing having substantially the same form factor as that of the removed power controller; and

installing the device within the current path at the location where the removed power controller was previously located.

54. A device for closing a current path between the line side and the load side of an electrical circuit:

a power controller having an opened position and a closed position and located within the current path, the power controller adapted to switch from the open position to the closed position in the presence of a first control supply and to maintain the closed position in the presence of a second control supply; and

a power supply adapted to;

when the power controller is open, output the first control supply having a first voltage for a first amount of time; and

after the first amount of time, output the second control supply having a second voltage sufficient to hold the power controller in the closed position, wherein the second voltage is less than the first voltage.

55. A device for interrupting a current path between the line side and the load side of an electrical circuit, the load side of the electrical circuit connected to an electrical load having an associated first operating current for a first amount of time and a second operating current for a second amount of time:

a power controller positioned within the current path and adapted to close the current path in the presence of a control supply and open the current path in the absence of the control supply;

a sensor system adapted to monitor the current in the current path and output a sensor signal indicative of a current condition within the current path; and

a logic controller adapted to receive the sensor signal and during the first amount of time compare the sensor signal to a first established criteria defined by the first operating current and remove the control supply from the power controller if the sensor signal does not satisfy the first established criteria and during the second amount of time compare the sensor signal to a second established criteria defined by the second operating current and remove the control supply from the power controller if the sensor signal does not satisfy the second established criteria.