Method and apparatus for loose wiring monitor

• US 8,125,345 B2
• Filed: 02/29/2008
• Issued: 02/28/2012
• Est. Priority Date: 03/01/2007
• Status: Active Grant

• Current Assignee: Power Monitors, Inc.
• Original Assignee: Power Monitors, Inc.
• Inventors: Curt, Walter, Mullins, Christopher
• Primary Examiner(s): HOFSASS, JEFFERY A
• Application Number:
  US12/040,711
• Publication Number:
  US 20080211683A1
• Time in Patent Office: 1,460 Days
• Field of Search: 340635-664, 340/687, 361 88- 92
• US Class Current: 340/652
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G01R 31/66 Testing of connections, e.g. of plugs or non-disconnectable joints testing for incorrect line connections G01R31/55
• CPC Class Codes: H02H 5/10 responsive to mechanical injury, e.g. rupture of line, breakage of earth connection

Abstract

A system is provided in which the voltage phases, neutral, and ground are monitored and an alarm is generated if specific trigger conditions are met. These conditions are indicative of a possible loose neutral, loose wiring, or general over/under voltage condition. Specific algorithms can be used to determine the possibility of a loose wiring condition, and if limits are met, various alarm modes are started.

Claims

1. A monitoring system comprising:

a monitoring device configured to detect a loose or intermittent connection of a wire; and

an alarm system configured to alert a user if the monitoring device detects the loose or intermittent connection,

wherein the monitoring device is configured to measure phase voltages in a single-phase system comprising two voltage legs, and determine that a loose neutral condition exists if one voltage leg rises in voltage, the other voltage leg falls in voltage, and the sum of the two voltages is within a threshold value of approximately twice a nominal voltage.

2. The monitoring system of claim 1, wherein the wire is a neutral wire.

3. The monitoring system of claim 1, wherein the wire is part of a single-phase system comprising two voltage legs, wherein the monitoring device is further configured to measure both voltage legs and a ground-to-neutral voltage.

4. The monitoring system of claim 1, wherein the wire is part of a three-phase system, wherein the monitoring device is further configured to measure all three phase voltages and a ground-to-neutral voltage.

5. The monitoring system of claim 1, wherein the monitoring device monitors a plurality of channels and wherein for each channel a scaled Root Mean Square (RMS) voltage is continuously computed or a proportional or representative signal comprising one of a peak voltage and an average rectified voltage is measured or computed.

6. The monitoring system of claim 1, wherein the monitoring device is configured to detect RF emanations, the RF emanations being characteristic of arcing or intermittent connections.

7. The monitoring system of claim 1, wherein the monitoring device is configured to measure a temperature using contactless infrared sensing or temperature sensors physically attached to a location, wherein heating of the location indicates a loose or intermittent connection of the wire.

8. The monitoring system of claim 1, wherein the monitoring device includes an audio or ultrasonic transducers configured to detect vibrations due to arcing or intermittent connections of the wire.

9. The monitoring system of claim 1, wherein the alarm system is configured to alert the user through a network.

10. A method comprising:

providing a monitoring device configured to detect a loose or intermittent connection of a wire;

and

alerting a user if the monitoring device detects the loose or intermittent connection,

wherein the monitoring device is configured to measure phase voltages in a single-phase system comprising two voltage legs, and determine that a loose neutral condition exists if one voltage leg rises in voltage, the other voltage leg falls in voltage, and the sum of the two voltages is within a threshold value of approximately twice a nominal voltage.

11. The method of claim 10, wherein the wire is a neutral wire.

12. The method of claim 10, wherein the wire is part of a single-phase system comprising two voltage legs, wherein the monitoring device is further configured to measure both voltage legs and a ground-to-neutral voltage.

13. The method of claim 10, wherein the wire is part of a three-phase system, wherein the monitoring device is further configured to measure all three phase voltages and a ground-to-neutral voltage.

14. The method of claim 10, wherein the monitoring device monitors a plurality of channels and wherein for each channel a scaled Root Mean Square (RMS) voltage is continuously computed or a proportional or representative signal comprising one of a peak voltage and an average rectified voltage is measured or computed.

15. The method of claim 10, wherein the monitoring device is configured to detect RF emanations, the RF emanations being characteristic of arcing or intermittent connections.

16. The method of claim 10, wherein the monitoring device is configured to measure a temperature using contactless infrared sensing or temperature sensors physically attached to a location, wherein heating of the location indicates a loose or intermittent connection of the wire.

17. The method of claim 10, wherein the monitoring device includes an audio or ultrasonic transducers configured to detect vibrations due to arcing or intermittent connections of the wire.

18. The method of claim 10, further comprising alerting the user through a network.