Fault Indicator with permanent and temporary fault indication

• US 7,023,691 B1
• Filed: 06/04/2003
• Issued: 04/04/2006
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: EO Schweitzer Manufacturing LLC
• Inventors: Fenske, Kurt James, Feight, Laurence Virgil
• Primary Examiner(s): CHANG, YEAN HSI
• Application Number:
  US10/454,850
• Time in Patent Office: 1,035 Days
• Field of Search: 361/681, 324/239, 324259-262, 324/522
• US Class Current: 324/510
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58

Abstract

A fault indicator for indicating the occurrence of a fault in an electrical conductor has a housing, a high capacity battery, a permanent fault display for indicating the occurrence of a permanent fault, a temporary fault display for indicating the occurrence of a temporary fault, a current sensor for sensing the load current in a monitored conductor, a microcontroller for determining when a fault condition occurs and for activating the permanent or temporary fault displays. Preferably, each display includes one or more LEDs. Upon detecting a fault, the microcontroller begins flashing the permanent fault LEDs. After a predetermined interval, the microcontroller again senses the load current. If the current is zero, the fault is permanent and the permanent LEDs continue to flash until a timed reset occurs. If the load current is present, the fault is temporary and the temporary LED is flashed until the timed reset. A light sensor is used to detect nighttime conditions, and microcontroller supplies reduced power to the LEDs at that time. Power to the LEDs is supplied in a repetitive pattern consisting of pulses followed by off time. Related methods are also disclosed.

Claims

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

a housing;

a battery;

display means for displaying the occurrence of a temporary fault and for displaying the occurrence of a permanent fault;

means for determining whether a fault is a temporary fault or a permanent fault based on at least one determination of whether said conductor has power applied thereto after an occurrence of the fault; and

circuitry in communication with the means for determining whether a fault is a temporary fault or a permanent fault to activate the permanent fault display means if the fault is determined to be a permanent fault or to activate the temporary fault display means if the fault is determined to be a temporary fault.

2. The fault indicator as claimed in accordance with claim 1, wherein said display means comprises two or more light emitting diodes (LEDs).

3. The fault indicator as claimed in accordance with claim 2, wherein said permanent fault display means comprises one or more LEDs of a first color and said temporary fault display means comprises one or more LEDs of a second color.

4. The fault indicator as claimed in accordance with claim 3, wherein

said means for determining whether the fault is a temporary fault or a permanent fault initially activates the permanent fault display means, and at a predetermined interval after the occurrence of the fault determines if said conductor has power applied thereto;

said circuitry continues to activate the permanent fault display means if power is no longer applied to said conductor at the predetermined interval, or

said circuitry deactivates the permanent fault display means and activates the temporary fault display means if power continues to be applied to said conductor at the predetermined interval.

5. The fault indicator as claimed in accordance with claim 4, wherein said fault indicator further comprises:

timed reset means for automatically resetting said fault indicator at a predetermined period after a fault is detected, said permanent fault display means or said temporary fault display means continuing to be activated until said fault detector is automatically reset.

6. The fault indicator as claimed in accordance with claim 3, wherein said fault indicator further comprises:

an ambient light sensor for sensing the ambient lighting conditions and for supplying an ambient light signal to said circuitry;

said circuitry responsive to the ambient light signal to reduce the power supplied to said one of more LEDs of the permanent fault display means and to said one or more LEDs of the temporary fault display means under low ambient light conditions.

7. The fault indicator as claimed in accordance with claim 3, wherein

said circuitry activates said at least one LED of the permanent fault display means and said at least one LED of the temporary fault display means with the repetitive pattern consisting of a plurality of current pulses followed by an off time.

8. The fault indicator as claimed in accordance with claim 7, wherein

said plurality of current pulses occur within about one second and said off time is greater than one second.

9. A method of indicating the occurrence of a temporary fault or of a permanent fault in a fault indicator that monitors an electrical conductor, the fault indicator including a housing, a battery, a permanent fault display and a temporary fault display, means for determining if a fault is a permanent fault or a temporary fault, and circuitry in communication with the means for determining if the fault is permanent or temporary to activate the respective permanent fault display or the temporary fault display, said method comprising the steps of:

determining whether the fault is a permanent fault or a temporary fault based on at least one determination of whether said conductor has power applied thereto after an occurrence of the fault; and

activating the permanent fault display if the fault is a permanent fault;

or

activating the temporary fault display if the fault is a temporary fault.

10. The method of indicating the occurrence of a temporary fault or of a permanent fault in accordance with claim 9, comprising the additional steps of:

initially activating the permanent fault display upon the occurrence of a fault;

determining whether power is applied to said conductor after a predetermined interval; and

continuing to activate the permanent fault display if power is no longer applied to said conductor;

or

deactivating the permanent fault display and activating the temporary fault display if power continues to be applied to said conductor after the predetermined interval.

11. The method of indicating the occurrence of a temporary fault or of a permanent fault in accordance with claim 9, wherein said fault indicator includes an automatic timed reset, said method comprising the additional step of:

continuing to activate the permanent fault display or the temporary fault display for a predetermined period after a fault is detected until the timed reset automatically resets the fault indicator.

12. The method of indicating the occurrence of a temporary fault or of a permanent fault in accordance with claim 9, wherein said fault indicator includes an ambient light sensor, said method comprising the additional steps of:

sensing the ambient lighting conditions with the ambient light sensor;

providing an ambient light signal from the ambient light sensor to said circuitry;

determining from said ambient light signal if low ambient light conditions exist, and if low ambient light conditions exist; and

reducing the power supplied to the permanent fault display or to the temporary fault display.

13. The method of indicating the occurrence of a temporary fault or of a permanent fault in accordance with claim 9, wherein the steps of activating the permanent fault display if the fault is a permanent fault, or activating the temporary fault display if the fault is a temporary fault include the step of:

providing the permanent fault display or the temporary fault display with a repetitive pattern consisting of a plurality of current pulses followed by an off time.

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

a housing;

a battery;

a permanent fault display for indicating that a permanent fault condition has occurred;

a temporary fault display for indicating that a temporary 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 microcontroller that is in communication with said load current signal from said current sensor to determine when a fault condition occurs; and

to determine whether the fault condition is permanent or temporary;

said microcontroller activating the permanent fault display if the fault is permanent or activating the temporary fault display if the fault is temporary.

15. The fault indicator as claimed in accordance with claim 14, wherein said permanent fault display comprises one or more LEDs of a first color and said temporary fault display comprises one or more LEDs of a second color.

16. The fault indicator as claimed in accordance with claim 15, wherein said fault indicator further comprises:

an ambient light sensor for sensing the ambient lighting conditions and for supplying an ambient light signal to said microcontroller;

said microcontroller responsive to the ambient light signal to reduce the power supplied to said one of more LEDs of the permanent fault display and to said one or more LEDs of the temporary fault display under low ambient light conditions.

17. The fault indicator as claimed in accordance with claim 15, wherein

said microcontroller activates said at least one LED of the permanent fault display and said at least one LED of the temporary fault display with a repetitive pattern consisting of a plurality of current pulses followed by an off time.

18. The fault indicator as claimed in accordance with claim 17, wherein

said plurality of current pulses occur within about one second and said off time is greater than one second.

19. The fault indicator as claimed in accordance with claim 14, wherein

said microcontroller initially activates the permanent fault display upon determining that a fault has occurred, and at a predetermined interval after the occurrence of the fault again determines if said conductor has power applied thereto;

said microcontroller continuing to activate the permanent fault display if power is no longer applied to said conductor at the predetermined interval, or

said microcontroller deactivating the permanent fault display and activating the temporary fault display if power continues to be applied to said conductor at the predetermined interval.

20. The fault indicator as claimed in accordance with claim 14, wherein said fault indicator further comprises:

a timed reset for automatically resetting said fault indicator at a predetermined period after a fault is detected, said permanent fault display or said temporary fault display continuing to be activated until said fault detector is automatically reset.