Apparatus and method for programmable trip settings in a faulted circuit indicator

• US 7,271,580 B1
• Filed: 11/12/2004
• Issued: 09/18/2007
• Est. Priority Date: 10/26/2001
• Status: Expired due to Term

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Feight, Laurence V., Fenske, Kurt J.
• Primary Examiner(s): Nguyen; Vinh P.
• Application Number:
  US10/988,007
• Time in Patent Office: 1,040 Days
• Field of Search: 324126-127, 324130-133, 324509-510, 324/532, 340/650, 340/664, 361/42, 361/35, 361/38, 361/59, 702/191
• US Class Current: 324/127
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

A fault indicator for indicating the occurrence of a fault in an electrical conductor is programmable, such as in the field, by placing a magnet in proximity to the housing of the fault indicator. A data processor senses the changed state of a magnetic switch and, after a predetermined delay, initiates a programming routine to enable selection of one of a plurality of trip settings for the fault indicator. During programming, display LEDs flash once for programming of the first trip setting, twice for setting of the second trip setting, and so forth. Removal of the magnet from proximity to the fault indicator while at the desired trip setting will result in programming of the fault indicator to that trip setting.

Claims

1. A fault indicator for indicating the occurrence of a fault in an electrical conductor, said fault indicator comprising:

a housing;

a battery at least partially internal to the housing;

a display for indicating that a fault condition has occurred;

a current sensor for sensing the load current in said conductor, and for providing a load current signal that is related to the load current;

a data processor drawing power from the battery, and that is in communication with said load current signal from said current sensor to determine the load current in said conductor, to program the fault indicator to one of a plurality of trip settings and to determine that a fault condition has occurred when the load current exceeds the programmed trip setting.

2. The fault indicator as claimed in accordance with claim 1, said fault indicator further comprising:

a memory that is accessed by said microcontroller, whereby said data processor stores the programmed trip setting in said memory.

3. The fault indicator as claimed in accordance with claim 1 wherein said data processor is manually programmable to one of said plurality of trip settings.

4. The fault indicator as claimed in accordance with claim 3 wherein said data processor actuates said display to indicate the trip setting selected during programming of the trip settings.

5. The fault indicator as claimed in accordance with claim 2 wherein said data processor resets the trip setting to that previously programmed and stored in memory if said conductor is deenergized and the load current is later restored.

6. The fault indicator as claimed in accordance with claim 1 wherein said plurality of trip settings are selected in the range of about 5 amperes to about 1200 amperes.

7. The fault indicator as claimed in accordance with claim 1 wherein said plurality of trip settings are selected from the group consisting of 25, 50, 100, 200, 400, 600, 800, 1000, and 1200 amperes.

8. The fault indicator as claimed in accordance with claim 1 wherein said data processor causes said display to display a fault condition for a predetermined time interval when the load current exceeds the programmed trip setting.

9. The fault indicator as claimed in accordance with claim 3 wherein a magnetic tool is used to initiate the programming to select one of the plurality of trip settings.

10. The fault indicator as claimed in accordance with claim 9 wherein said magnetic tool causes a magnetic switch to change state from open to closed or from closed to open, the magnetic switch in electrical communication with the data processor.

11. The fault indicator as claimed in accordance with claim 10 wherein said data processor senses the change in state of the magnetic switch and initiates a trip programming routine if the magnetic switch remains closed for a predetermined amount of time.

12. The fault indicator as claimed in accordance with claim 11 wherein said trip programming routine starts at a first trip setting and delays before moving to a second trip setting.

13. The fault indicator as claimed in accordance with claim 12 wherein removal of said magnetic tool from proximity to said fault indicator before the trip setting routine moves to a second trip setting will program the fault indicator at the first trip setting.

14. The fault indicator as claimed in accordance with claim 12 wherein said display flashes once to indicate that the trip programming routine is at the first trip setting.

15. The fault indicator as claimed in accordance with claim 12 wherein said display flashes twice to indicate that the trip programming routine is at the second trip setting.

16. The fault indicator as claimed in accordance with claim 1 wherein said fault indicator is programmed to one of the plurality of trip settings after the fault indicator is installed on the electrical conductor.

17. A method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor, wherein said fault indicator includes a housing, a battery, a display for displaying a fault condition, a current sensor and a data processor, said method comprising the steps of:

sensing the load current in said conductor with the current sensor;

providing a load current signal from the current sensor that is related to the load current in the conductor;

providing a plurality of selectable trip settings for said fault indicator;

determining the load current in said conductor based upon the load current signal for the sensor;

selecting one of the plurality of trip settings by initiating a programming routine; and

displaying a fault condition if the load current exceeds the selected trip setting.

18. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

storing the selected trip setting in a memory for recall by the data processor.

19. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

displaying the trip level being programmed during running of the programming routine.

20. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

manually initiating said programming routine by placement of a magnet in proximity to said fault indicator.

21. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

resetting the trip setting to that previously programmed and stored in memory if the conductor is deenergized and the load current in the conductor is later restored.

22. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

flashing the display once to indicate when the programming routine is programming the fault indicator to a first trip setting; and

flashing the display twice to indicate when the programming routine is programming the fault indicator to a second trip setting.

23. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 22, further comprising the additional step of:

terminating said programming routine at the desired trip setting by removal of a magnet in proximity to said fault indicator before said programming routine moves to the next trip setting.

24. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 20, further comprising the additional step of:

causing a magnetic switch to change state from open to closed or from closed to open in response to the magnet being placed in proximity to the fault indicator.

25. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 24, further comprising the additional step of:

sensing the change in state of the magnetic switch from open to closed or from closed to open at the data processor; and

initiating said programming routine to program the fault indicator to one of said plurality of trip settings.

26. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 20, further comprising the additional step of:

programming said fault indicator in a selected one of said plurality of trip settings by removing the magnet from proximity to said fault indicator while the display indicates that the programming routine is at the selected trip setting.

27. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

selecting the trip settings from a range of about 5 to about 1200 amperes.

28. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

selecting the trip settings from the group consisting of 25, 50, 100, 200, 400, 600, 800, 1000, and 1200 amperes.

29. The method of programming a trip setting in a fault indicator that detects faults in a monitored electrical conductor in accordance with claim 17, further comprising the additional step of:

initiating the programming routine to select one of the plurality of trip settings after the fault indicator has been installed on said conductor.