Wire break locator and method of use

Details Wire break locator and method of use Wire break locator and method of use

1999-04-27

2001-04-10

Metjahic, Safet (Department: 2858)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

For fault location

C324S527000

Reexamination Certificate

active

06215314

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a system for locating a break in a single conductor wire. More particularly, this invention relates to a system for locating a break in a buried single conductor wire such as used with conventional electronic pet confinement systems.
2. Description of the Related Art
Numerous wire bounded pet containment systems have been installed in the United States. The wire defines the perimeter of the area in which the pet is to be confined. A transmitter generates a low strength radio frequency signal which is carried by the wire. A receiver worn by the pet to be confined is tuned to the frequency of the signal carried by wire. Should the pet stray too close to the boundary, a correction signal is generated.
The wire will typically provide many years of service; however, it is subject to potential breakage. Generally, the wire is an 18 gauge, insulated, unshielded, stranded wire. For most installations, the wire is buried between two (2) and six (6) inches underground. The length of the wire may vary between less than 100 yards for a small enclosure and more than 1000 yards for a large enclosure. Accordingly, considerable time and expense is invested in burying the wire and landscaping over the buried wire. Should the wire suffer a break, finding the location of the break is nearly impossible without digging up the entire wire. Further, unnecessary digging to visually inspect the wire increases the risk of additional damage to the wire.
Various devices have been developed for locating breaks in underground wires. Often an ohmmeter which measures the resistance of a wire is used. However, variations in the depth at which the wire is buried lead to fluctuations in the measured resistance. In the case of the pet confinement system, the wire depth can vary without adversely affecting the performance of the pet confinement function rendering the ohmmeter ineffective in locating a break in the buried wire.
Another device used to locate problems with underground wires is a time domain reflectometer (TDR). The TDR looks at the impedance of a wire pair, such as a twisted wire pair or coaxial cable. However, where the impedance of the wire is not constant, the reading of the TDR is ambiguous. Further, the TDR is typically too expensive for the average consumer, thus limiting its use to utility and telephone companies. Accordingly, the TDR is not a viable option for detecting breaks in a single conductor wire used to bound a pet confinement area.
Yet another technique utilizes a radio frequency (RF) signal transmitted through the wire. By monitoring the radio frequency signal, it is possible to determine the approximate location of wire buried underground. However, because the wire acts as an antenna in this technique, the propagation of the RF signal does not allow a determination of a reasonably close approximation of the location of the break in the wire.
Therefore, it is an object of the present invention to provide a system for locating breaks in continuity in a wire, especially those buried underground.
It is another object of the present invention to provide a system which is inexpensive and simple for use in residential applications.
It is a further object of the present invention to provide a system for locating breaks in an unshielded single conductor wire.
It is yet another object of the present invention to provide a method for locating breaks in continuity in a wire.
BRIEF SUMMARY OF THE INVENTION
A system for locating a break in an unshielded, insulated, single conductor wire is provided. The system for locating a break in a wire, or wire break location system, measures the signal strengths of two distinct signals propagating through each of the wire segments defined by the break in a wire.
The wire break location system includes a transmitter electrically connected to both ends of a wire having a break at an undetermined location. In a typical application, the wire is buried between two and six inches underground making location of the break difficult. The transmitter generates two distinct low power, continuous wave (CW) radio frequency (RF) signals. A first CW-RF signal is transmitted in a first direction around the wire. Simultaneously, a second CW-RF signal is transmitted in the opposite direction through the wire. Because of the break in the wire, the first signal only propagates through the portion of the wire between the transmitter and the break in the first direction. Similarly, the second signal only propagates through the portion of the wire between the transmitter and the break in the second direction. Each signal radiates outwardly from the wire to a range corresponding to the signal strength. Proximate the end of each wire segment, each of the first signal and the second signal begins to attenuate providing information as to the location of the break.
A locator is tuned to receive each of the first signal and the second signal. In the preferred embodiment, the locator is an amplitude modulated (AM) radio receiver. The operator searching for the break in the wire carries the locator and follows either signal starting at the transmitter. As the operator approaches the location of the break, the signal strength of the signal being followed diminishes until the signal can longer be picked up. If the operator continues forward, the locator will pick up the other signal and the signal strength will increase as the operator moves away from the break. In this manner, the operator can determine the location of the break. By placing the locator near the ground, the location of the break can be determined within a margin of about six inches. Accordingly, no unnecessary digging is required to locate the break in the wire.
Further, a method for locating in a break in a wire is described. Two distinct CW-RF signals are generated. Each signal has a unique predetermined frequency and a signal strength selected to limit the broadcast radius of the signal to an approximate maximum range between three and six feet from the wire. The signals are transmitted in opposite directions through the wire. A locator is employed to follow a selected one of the signals along the length the wire using an audible tone corresponding the received signal generated by the locator. The volume of the audible tone decreases as a result of signal attenuation as the locator is moved toward the break.


REFERENCES:
patent: 5914608 (1999-06-01), Wissman

Affiliated with

Also associated with

Rating

Wire break locator and method of use does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Wire break locator and method of use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wire break locator and method of use will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2465121