Remote light indication fault indicator with a timed reset circuit and a manual reset circuit

• US 6,133,724 A
• Filed: 06/29/1998
• Issued: 10/17/2000
• Est. Priority Date: 06/29/1998
• Status: Expired due to Term

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: E.O. Schweitzer Manufacturing Compay, LLC
• Inventors: Feight, Laurence V., Schweitzer, Edmund O. Jr.
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Nguyen, Vincent Q.
• Application Number:
  US09/106,434
• Time in Patent Office: 841 Days
• Field of Search: 324/508, 324/509, 324/512, 324/522, 324/524, 324/541, 324/544, 324/551, 324/555, 324/556, 324/127, 324/133, 324/149, 340/660, 340/661, 340/662, 340/664, 340/651, 340/691.1, 361/93.1, 361/93.4, 361/94, 361/71, 361/75, 361/59, 361/87
• US Class Current: 324/133
• CPC Class Codes: G01R 15/148 involving the measuring of a magnetic field or electric field G01R15/18, G01R15/20, G01R15/24, G01R15/26 take precedence
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

A fault indicator contained within a protective equipment closure of the type used to house pad-mounted components of a power distribution system detects the occurrence of a fault current in a monitored conductor and provides a light indication thereof. The fault indicator includes a circuit monitoring module, having an integral fault indicator flag module, and a remote fault indicator light module. A status-indicating flag is rotatably mounted in the integral fault indicator flag module. The flag is positioned in either a reset indicating position or a fault indicating position by a magnetic pole piece, which is magnetized in one magnetic direction or the other by momentary application of a current in one direction or the other to an actuator winding on the pole piece. A magnetically actuated reed switch in an auxiliary magnetic circuit comprising an auxiliary pole piece magnetized by the actuator winding and a bias magnet magnetically aligned to oppose the reset magnetic orientation and reenforce the trip magnetic orientation of the magnetic pole piece closes upon occurrence of the fault current to connect an internal battery to an LED contained within the remote fault indicator light module so that the LED is visible from the exterior of the protective equipment enclosure. The light indication of the fault occurrence may be reset automatically by a timed reset circuit or manually by a manual reset circuit.

Claims

1. A fault indicator for providing indication of a fault current outside the exterior surface of an electrical equipment enclosure following the occurrence of a fault current in an electrical conductor within the enclosure and for resetting the indication of said fault current, comprising:

a circuit monitoring module;

a remote fault indicator light module operatively connected to said circuit monitoring module and mounted to said exterior surface of said enclosure;

a battery contained within said circuit monitoring module;

a light source contained within said remote fault indicator light module operable from said battery;

a magnetic circuit including a magnetic pole piece, a magnetically actuated switch and a bias magnet, said bias magnet having a magnetic polarity which opposes a magnetic field in said magnetic pole piece in one direction, and reenforces a magnetic field in said magnetic pole piece in the other direction, whereby said magnetically actuated switch is conditioned to open in response to a magnetic field in said one direction and close in response to a magnetic field in said other direction;

circuit means including a magnetic winding in magnetic communication with said magnetic pole piece and responsive to the current in the monitored conductor for developing a magnetic field in said pole piece in a direction to condition said switch open during normal current flow in the monitored conductor, and for developing a magnetic field in said pole piece in said opposite direction to condition said switch closed upon occurrence of a fault current in the conductor;

said magnetically actuated switch connecting said battery to said light source;

said light source providing a light indication of said occurrence of said fault current; and

a timed reset circuit for maintaining said fault indication for a predetermined period of time and resetting said light source upon expiration of said predetermined period of time.

2. A fault indicator as defined in claim 1 further comprising a manual reset circuit.

3. A fault indicator as defined in claim 2 wherein said manual reset circuit comprises a magnetically actuated manual reset switch contained within said remote fault indicator light module.

4. A fault indicator as defined in claim 3 wherein said magnetically actuated manual reset switch is connected to a timing capacitor included within said timed reset circuit means.

5. A fault indicator as defined in claim 1 wherein said magnetic pole piece includes a pair of spaced-apart magnetic poles, and said magnetically actuated switch is disposed between said poles.

6. A fault indicator as defined in claim 5 wherein said magnetically actuated switch comprises a reed switch.

7. A fault indicator as defined in claim 6 wherein the axis of said reed switch is aligned generally parallel to the axis of said monitored conductor.

8. A fault indicator as defined in claim 7 wherein said magnetic pole piece is generally U-shaped.

9. A fault indicator as defined in claim 1 wherein said remote fault indicator light module comprises a bolt-shaped housing.

10. A fault indicator as defined in claim 9 wherein said bolt-shaped housing comprises a transparent head.

11. A fault indicator as defined in claim 1 wherein said light source comprises a light emitting diode.

12. A fault indicator as defined in claim 11 further comprising a flasher circuit for flashing said light emitting diode.

13. A fault indicator as defined in claim 1 further comprising a second magnetically actuated switch contained within said remote fault indicator light module connecting said battery to said light source.

14. A fault indicator for providing indication of a fault current outside the exterior surface of an electrical equipment enclosure following the occurrence of a fault current in an electrical conductor within the enclosure and for resetting the indication of said fault current, comprising:

a circuit monitoring module having an integral fault indicator flag module;

a remote fault indicator light module operatively connected to said circuit monitoring module;

a battery contained within said circuit monitoring module;

a light source contained within said remote fault indicator light module and operable from said battery;

a magnetic circuit including a magnetic pole piece, a magnetically actuated switch and a bias magnet, said bias magnet having a magnetic polarity which opposes a magnetic field in said magnetic pole piece in one direction, and reenforces a magnetic field in said second magnetic pole piece in the other direction, whereby said magnetically actuated switch is actuated open in response to a magnetic field in said one direction and closed in response to a magnetic field in said other direction;

circuit means including a magnetic winding in magnetic communication with said magnetic pole piece and responsive to the current in the monitored conductor for developing a magnetic field in said one direction in said pole piece to condition said magnetically actuated switch closed upon occurrence of a fault current in the conductor;

said magnetically actuated switch connecting said battery to said light source;

said light source providing a light indication of said occurrence of said fault current;

a timed reset circuit for maintaining said fault indication for a predetermined period of time and resetting said light source upon expiration of said predetermined period of time; and

a manual reset circuit including a magnetically actuated manual reset switch contained within said remote fault indicator light module.

15. A fault indicator as defined in claim 14 wherein said timed reset circuit comprises a timing capacitor.

16. A fault indicator as defined in claim 15 wherein said magnetically actuated manual reset switch is connected to said timing capacitor.

17. A fault indicator as defined in claim 14 wherein said magnetic pole piece includes a pair of spaced-apart magnetic poles, and said magnetically actuated switch is disposed between said poles.

18. A fault indicator as defined in claim 17 wherein said magnetically actuated switch includes a pair of projecting leads, and said leads are mechanically connected to but electrically isolated from said magnetic poles.

19. A fault indicator as defined in claim 18 wherein said magnetically actuated switch comprises a reed switch.

20. A fault indicator as defined in claim 19 wherein the axis of said reed switch is aligned generally parallel to the axis of said monitored conductor.

21. A fault indicator as defined in claim 14 wherein said light source comprises a light emitting diode.

22. A fault indicator as defined in claim 21 further comprising a flasher circuit for flashing said light emitting diode.

23. A fault indicator as defined in claim 14 further comprising a second magnetically actuated switch contained within said remote fault indicator light module connecting said battery to said light source.

24. A fault indicator for providing indication of a fault current outside the exterior surface of an electrical equipment enclosure following the occurrence of a fault current in an electrical conductor within the enclosure and for resetting the indication of said fault current, comprising:

a circuit monitoring module having an integral fault indicator flag module;

a remote fault indicator light module operatively connected to said circuit monitoring module and mounted to said exterior surface of said enclosure;

a battery contained within said circuit monitoring module;

a light source contained within said remote fault indicator light module and operable from said battery;

an indicator flag rotatbly mounted in said integral fault indicator flag module and viewable from the exterior of said flag module;

a first magnetic pole piece having magnetic poles in magnetic communication with said indicator flag, said flag assuming a reset-indicating position in response to a magnetic field in said first magnetic pole piece in one direction and a trip-indicating position in response to a magnetic field in said first magnetic pole piece in the other direction;

a magnetically actuated switch;

a second magnetic pole piece having magnetic poles in magnetic communication with said magnetically actuated switch, and a bias magnet opposing a magnetic field in said second magnetic pole piece in said one direction and reenforcing a magnetic field in said second magnetic pole piece in said other direction whereby said magnetically actuated switch is actuated to open in response to a magnetic field in said one direction and is actuated closed in response to a magnetic field in said second magnetic pole piece in said other direction;

circuit means including a magnetic actuator widning in magnetic communication with said first and second magnetic pole pieces for inducing magnetic field in said one direction in each of said pole pieces when said fault indicator is in a reset state, and in said other direction when said fault indicator is in a trip state;

said magnetically actuated switch connecting said battery to said light source;

said light source providing a light indication of occurrence of said fault current;

a timed reset circuit for maintaining said fault indication for a predetermined period of time and resetting said light source upon expiration of said predetermined period of time; and

a manual reset circuit including a magnetically actuated manual reset switch contained within said remote fault indicator light module.

25. A fault indicator as defined in claim 24 wherein said timed reset circuit means comprises a timing capacitor.

26. A fault indicator as defined in claim 25 wherein said magnetically actuated manual reset switch is connected to said timing capacitor.

27. A fault indicator as defined in claim 24 wherein said auxiliary magnetic pole piece includes a pair of spaced-apart magnetic poles, and said magnetically actuated switch is disposed between said poles.

28. A fault indicator as defined in claim 27 wherein said magnetically actuated switch includes a pair of projecting leads, and said leads are mechanically connected to but electrically isolated from said magnetic poles.

29. A fault indicator as defined in claim 28 wherein said magnetically actuated switch comprises a reed switch.

30. A fault indicator as defined in claim 29 wherein the axis of said reed switch is aligned generally parallel to the axis of said monitored conductor.

31. A fault indicator as defined in claim 24 wherein said auxiliary magnetic pole piece is generally U-shaped.

32. A fault indicator as defined in claim 31 wherein said actuator winding is wound on a portion of said first magnetic pole piece and a portion of said second magnetic pole piece.

33. A fault indicator as defined in claim 24 wherein said light source is a light emitting diode.

34. A fault indicator as defined in claim 33 further comprising a flasher circuit for flashing said light emitting diode.

35. A fault indicator as defined in claim 24 further comprising another magnetically actuated switch contained within said remote fault indicator light module connecting said battery to said light source.