Patent Application
20060192545
The present invention generally relates to the field of test equipment, and more particularly to an elongate voltage detection pole to sense the presence of an alternating current (AC) signal voltage at a distance.
Due to problems with maintenance, corrosion or the poaching of electricity supplied by a public utility company, exposed electrical wire may come in contact with conducting surfaces, such as metal utility poles, manhole covers or puddles of water, resulting in electrified “hot spots” in public areas. These hotspots can be harmful, and even fatal, if contacted by a passerby. Additionally, the area of these hotspots can be very irregular and difficult to detect.
Thus, there is a need for a system and techniques for sensing an electrified metal utility pole or other structure to allow for proper repair before someone is injured. Additionally, there is a need for a system and techniques for allows an alternating current to be sensed at a distance before an individual moves near the electrified element. Moreover, there is a need for a system and techniques which allows a user to adjust the sensitivity of sensing system by having a high sensitivity when searching at a distance and then reducing the sensitivity when moving closer to the electrified structure.
Additionally, there is a need for a voltage sensing system which is mounted to a utility pole or other structure and provides an indication when the utility pole is electrified.
In one aspect of the present invention, an elongate probe of at least two feet in length for alerting a user to the presence of electrical energy includes an antenna to sense radiated electrical energy and an indicator to alert a user when activated. Circuitry determines when the sensed electrical energy meets a user adjustable threshold and activates the indicator when the sensed electrical energy meets the user adjustable threshold. An adjustor allows for selecting the user adjustable threshold.
A more complete understanding of the present invention, as well as further features and advantages of the invention, will be apparent from the following detailed description and the accompanying drawings.
The following detailed description of preferred embodiments refers to the accompanying drawings which illustrate specific embodiments of the invention. In the discussion that follows, specific systems and techniques for sensing alternating current are disclosed. Other embodiments having different structures and operations for the manufacture of other systems do not depart from the scope of the present invention.
A housing portion 106 affixed to the elongate shaft 102 houses processing electronics 108 connected to the antenna 104 for processing the signal received by the antenna 104 and determining if the antenna 104 is near a conductor conducting an AC signal having a sensed amplitude above a user selectable threshold, as described in greater detail below. The housing portion 106 may also comprise an audible buzzer 107 and a visual indicator 110 controlled by the processing electronics 108 for communicating the presence of a sensed alternating current to a user. Batteries 109 may suitably power the processing electronics. A handle 112, for holding and manipulating the voltage detection pole 100, is also attached to the housing portion 106. The handle 112 holds an adjustment element 114 connected to the processing electronics 108 for controlling the user selectable threshold. Alternately, the housing portion 106 may hold the adjustment element 114.
The sensitivity of the voltage detection pole 100 is the voltage threshold level at which the voltage detection pole 100 will provide an indication to the user of sensed AC voltage. As described in U.S. Pat. No. 6,828,767, this sensitivity is determined by the value of the resistor 306. In order to allow the user of the voltage detection pole 100 to select the voltage threshold level, the resistor 306 may suitably comprise a variable resistor controlled by adjustment element 114, allowing a user to dynamically control the sensitivity of the voltage detection pole 100 by turning a dial. Alternately, the adjustment element 114 may comprise a switch which switches additional resistive elements into or out of a parallel configuration with the resistor 306 to raise or lower the voltage threshold level. By allowing the value to the resistor 306 to be increased to 1.5 Gohms, the voltage threshold level may be lowered to 2 volts RMS or lower. By decreasing the value of the resistor 306 to 150 Mohms, the voltage threshold level may be raised to 16 volts RMS.
In order to allow a user to safely determine if an AC voltage is present in an area, the voltage detection pole 100 is preferably at least 2 feet in length, more preferably at least 2.5 feet in length, and in particular at least 3 feet in length, to allow the user detect the AC voltage from a distance without approaching the voltage source too closely. A typical prior art device that has a short length may put the user in danger by forcing the user to approach the AC voltage and risk electric shock. The length of the voltage detection pole 100, and thus the extension of the antenna 104 from the user, allows the user to quickly move the tip of the voltage detection pole 100 around an area with the voltage threshold level set to a low level and determine if there is any AC voltage present. Thus, in addition to keeping the user further away from dangerous voltages, the length of at least 2 feet allows for more efficient testing of an area by increasing the reach of the test and allowing the end of the voltage detection pole 100 to be quickly moved about. Additionally, the length of at least 2 feet allows the user to test areas or structures that are high off the ground. Moreover, the length of at least 2 feet allows a user to extend the voltage detection pole through an open window of a vehicle to test objects near the vehicle.
If AC voltage is detected, the user may increase the voltage threshold level as needed while continuing the search to further narrow the area having the AC voltage. In other words, a user may adjust the sensitivity of voltage detection pole 100 by controlling the adjustment element 114 to select a high sensitivity when searching at a distance and then reducing the sensitivity when moving closer to the electrified structure to further narrow the search to the specific hot spot.
In another aspect of the present invention, a voltage sensing system is adapted for attachment a utility pole or other structure and provides an indication when the utility pole is electrified.
The pole mounted sensor 502 may also include an AC generator 512 for testing the sensor 502. The AC generator 512 may suitably generate an AC signal of 2-30 volts RMS. When the AC generator 512 is operating and producing a signal, the processing electronics 507 will sense a corresponding signal received by the antenna 504 and cause the LED 506 and buzzer 508 to activate. The AC generator may be activated remotely, utilizing a radio frequency (RF) or infrared (IR) signal, by someone holding an testing unit 520 which communicates with the pole mounted sensor 502. The testing unit 520 comprises a transmitter 522 controlled by a user activated switch 524 and powered by a battery 526. When a user activates the switch 524, the transmitter 522 sends a signal to the receiver 514 of the sensor 502, which in turn, activates the AC generator 512. Thus, someone responsible for verifying that no hot spots exist may first view the pole mounted sensor 502 to ensure that the sensor 502 is not reporting an electrified pole and the use the testing unit 520 to test the pole mounted sensor 502 to ensure proper operation. Optionally, the AC generator 512 may be packaged separately from the sensor 502.
Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the invention has other applications in other environments. This application is intended to cover any adaptations or variations of the present invention. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described herein.
