Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – For fault location
Patent
1993-03-18
1994-12-13
Arana, Louis
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
For fault location
324613, 324501, 324520, 324 7623, 455 673, G01R 2300
Patent
active
053732413
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The subject invention relates to the detection of radio frequency spectra and of electric arcs, and to systems for acting in response to such radio frequency spectra or to systems for preventing damage from electric arcs.
BACKGROUND
Given the fact that electric arcs or sparks were the first means for wireless communication, it may be surprising that there persisted a need for detecting a spectrum of radio frequencies in radio frequency noise, such as generated by an electric arc in an electric circuit. However, such a persisting need has been particularly emphasized by electrical fires and other serious damage caused by accidental arcs in electric power supply systems and other circuits. In this respect, while fuses and circuit breakers are capable of preventing serious overload conditions, they have been generally ineffective to prevent electrical fires and other damage from accidental arcs and sparks which frequently occur and persist at current levels below the level at which the fuse will blow or the circuit breaker has been set to trip.
On the other hand, electrical fault detection has been practiced for a long time. For instance, U.S. Pat. No. 1,462,053, by H. M. Stoller, issued Jul. 17, 1923, and 3,308,345 by A. R. Van Cortlandt Warrington, issued Mar. 7, 1967, show different uses of resonant circuitry for fault detection. U.S. Pat. No. 3,728,620, by J. L. Heins, issued Apr. 17, 1973, constitutes the transmission line as a resonant circuit for fault indication and location, utilizing a variable frequency source coupled to one end of the line. U.S. Pat. No. 3,751,606, by C. W. Kaiser, Jr., issued Aug. 7, 1973, and 3,904,839, and 4,229,626, by J. T. Peoples, issued Sep. 9, 1975 and Oct. 21, 1980, respectively, disclose loop fault locators using demodulators, phase comparators, and other electronic circuits.
U.S. Pat. No. 4,006,410, by D. R. Roberts, issued Feb. 1, 1977, proposed pinpointing the location of corona discharges in an electrical system by processing only those high-frequency components that do not propagate along the wires of the system. U.S. Pat. No. 4,466,071, by B. D. Russell, Jr., issued Aug. 14, 1984, disclosed high impedance fault detection apparatus and methods using a microcomputer system. U.S. Pat. No. 4,543,524 by R. M. Bulley, issued Sep. 24, 1985, may be noted as of interest in the spectrum analyzer area.
Despite this wealth of information and prior proposals, electrical fires and other damage caused by arcs and sparks have continued to devastate electric power supply and other systems, as well as buildings housing them and forests and neighborhoods in which they are located.
Also, vulnerability to false alarms has been a discouraging problem, inasmuch as switching transients, emissions from radio and television transmitters and other sources can easily trigger false alarms in arc detectors.
In another vein, machinery, circuitry, and apparatus often break down and become damaged in a manner or to an extent that could have been prevented if there had been an early detection of unusual arcing. For instance, commutators of electric motors are often damaged when their carbon brushes wear out, since the metallic brush holder springs then rub against the commutator. Since such wear is accompanied by heavy arcing, an early detection of such arcing could signal the need for preventive action. This is, of course, only a representative example of fields where reliable arc detection could be useful.
SUMMARY OF THE INVENTION
It is a general object of this invention to overcome the disadvantages and to meet the needs set forth above or otherwise expressed or implicit herein.
It is a germane object of this invention to provide improved methods and apparatus for detecting a spectrum of distinct instantaneous radio frequencies in radio frequency noise.
It is a related object of this invention to provide improved methods and apparatus for detecting the occurrence of arcs in electric circuits.
Other objects of the invention will become apparent in the further course
REFERENCES:
patent: 1462053 (1923-07-01), Stoller
patent: 3308345 (1967-03-01), Van Cortlandt
patent: 3555413 (1971-01-01), Matsuba
patent: 3728620 (1973-04-01), Heins
patent: 3751606 (1973-08-01), Kaiser, Jr.
patent: 3820018 (1974-06-01), Beasley et al.
patent: 3869665 (1975-03-01), Kenmochi et al.
patent: 3904839 (1975-09-01), Peoples
patent: 4006410 (1977-02-01), Roberts
patent: 4072899 (1978-02-01), Shimp
patent: 4229626 (1980-10-01), Peoples
patent: 4466071 (1984-08-01), Russell, Jr.
patent: 4543524 (1985-09-01), Bulley
patent: 4609866 (1986-09-01), Loftness
patent: 4785223 (1988-11-01), Hank et al.
patent: 4967158 (1990-10-01), Gonzalez
RF/IF Signal Processing Guide, SF-89/90, pp. 8 etc., 1989.
Christopher Schiebold, "Theory and Design of the Delay Line Discriminator for Phase Noise Measurements." 176 Microwave J., vol. 26 (1983).
Chong-Yung Chi, et al, "Roundoff Noise Analysis for Digital Signal Power Processors, etc.", IEEE Trans. ASSP-35 (1987) No. 6, pp. 784-794.
Motorola Linear and Interface Intergrated Circuits Catalog (1988) pp. 8-65 to 8-70 and 2-57 to 2-60.
Microwaves & RF (Jul. 1990) F132-2.
Ham, Jr. Howard M.
Keenan James J.
Arana Louis
Hendry Mechanical Works
Solis Jose M.
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