Power line testing device with signal generator and signal detector
First Claim
1. A transmitter for placing an identification signal on an AC power distribution circuit, comprising:
- at least first and second output terminals for connection to different ones of a plurality of conductors of the power distribution circuit, and a signal generator coupled to the first and second output terminals, the signal generator superimposing an identification signal on an alternating current carrier signal, the identification signal having a repetition period different from the period of the carrier signal.
1 Assignment
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Accused Products
Abstract
A power line testing device with signal generator and signal detector incorporates a DC power supply that is capable of generating DC power from a miswired outlet, as long as there is a hot conductor and a return path. The device includes a signal generator which generates a signal that is easily distinguishable from noise. The transmitter further includes a spark gap for creating an arc used to test the function of an ACFI device connected to the branch under test. The transmitter further detects the integrity of circuit ground by measuring its impedance. A receiver of the device measures the elapsed time of the testing signals, permitting a more sophisticated test of interrupter device function.
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Citations
31 Claims
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1. A transmitter for placing an identification signal on an AC power distribution circuit, comprising:
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at least first and second output terminals for connection to different ones of a plurality of conductors of the power distribution circuit, and a signal generator coupled to the first and second output terminals, the signal generator superimposing an identification signal on an alternating current carrier signal, the identification signal having a repetition period different from the period of the carrier signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An electrical wiring testing device for testing whether hot, neutral and ground conductors have been correctly connected to respective hot, neutral and ground terminals of an AC power outlet, comprising:
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hot, neutral and ground terminals for plugging into hot, neutral and ground receptacles of an AC power outlet;
a sensing, circuit coupled to the hot, neutral and ground terminals of the device for sensing one of a plurality of wiring conditions recognizable by the sensing circuit, the conditions including a correct wiring condition and a reversed hot and neutral wiling condition; and
indicator circuitry coupled to the sensing circuit for indicating which of the wiling conditions is present. - View Dependent Claims (8)
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9. A transformerless power supply for supplying DC power, comprising:
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hot, neutral and ground input terminals for respective connection to hot, neutral and ground terminals of an AC power outlet;
an AC/DC conversion circuit having a DC power output and an input; and
a hot and return path conductor recognition circuit interposed between the hot, neutral and ground input terminals and the input of the conversion circuit and supply ground, the recognition circuit supplying power to the input of the conversion circuit even where the AC power outlet has been miswired, as long as one of the terminals of the AC power outlet is connected to a hot conductor and another of the terminals of the AC power outlet is connected to a return path. - View Dependent Claims (10, 11, 13, 16, 17, 18, 19)
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12. An AC power branch circuit testing device, comprising:
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hot, neutral and ground terminals respectively connectable to a hot receptacle, a neutral receptacle and a grounding point of an AC power outlet;
a ground integrity circuit coupled to the ground terminal and detecting whether a parasitic resistance of the connection between the grounding point and ground exceeds a predetermined maximum; and
an indicator coupled to the ground integrity circuit for indicating whether the detected parasitic resistance exceeds the predetermined maximum.
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14. A ground integrity testing device, comprising:
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a generator circuit having an output for generating a signal at a predetermined frequency;
a sensing circuit coupled between a voltage supply and a grounding point to be tested;
a coupling circuit coupling the generator circuit with the sensing circuit for transmitting the second signal of the predetermined frequency to the sensing circuit, any parasitic impedance connected between the sensing circuit grounding point and ground causing a phase shift to the second signal;
a detection circuit coupled to the sensing circuit for detecting the phase shift of the second signal; and
an indicator coupled to the detection circuit and indicating a ground integrity problem if the phase shift exceeds a predetermined amount.
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15. An AC power branch circuit locator device, comprising:
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a transmitter for placing an identification signal on a first AC power distribution circuit, at least first and second output terminals for connection to different ones of a plurality of conductors of the first power distribution circuit, a signal generator superimposing an identification signal on an alternating current carrier signal, the identification signal having a repetition period different from the period of the carrier signal; and
a receiver for use in a location remote from the transmitter but in proximity to the first AC power distribution circuit, the receiver operable to detect the identification signal.
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20. A receiver for use in locating a first AC power branch circuit, comprising:
- A sensing circuit for detecting, in a proximate one of a plurality of AC power branch circuits including the first AC power branch circuit, an identification signal, the identification signal being strongest on the first AC power branch circuit;
a memory coupled to the sensing circuit for storing a strength of the detected identification signal; and
a comparator coupled to the memory for comparing the strength of a currently sensed identification signal to a stored identification signal; and
an indicator coupled to the comparator and providing an indication to the user that a currently sensed identification signal has a strength which is at least as great as that of the stored identification signal, thereby permitting the user to identify the first AC power branch circuit. - View Dependent Claims (21)
- A sensing circuit for detecting, in a proximate one of a plurality of AC power branch circuits including the first AC power branch circuit, an identification signal, the identification signal being strongest on the first AC power branch circuit;
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22. A receiver for use in locating a first AC power branch circuit, comprising:
- A sensing circuit for detecting, in a proximate one of a plurality of AC power branch circuits including the first AC power branch circuit, an identification signal, the identification signal being strongest on the first AC power branch circuit; and
A signal strength indicator coupled to the sensing circuit and giving and indication of signal strength which varies according to the magnitude off the sensed signal strength. - View Dependent Claims (23, 26, 28)
- A sensing circuit for detecting, in a proximate one of a plurality of AC power branch circuits including the first AC power branch circuit, an identification signal, the identification signal being strongest on the first AC power branch circuit; and
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24. A transmitter for an AC power branch circuit testing device connectable to HOT, NEUTRAL and GROUND conductors of an AC power branch circuit, comprising:
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a wiring scenario analyzer of the transmitter detecting which of the conductors are energized and which provide a return path, an indicator circuit of the transmitter coupled to the wiring scenario analyzer to uniquely indicate which of a plurality of wiring scenarios is present;
a ground integrity testing circuit of the transmitter coupled to the GROUND conductor of the power branch circuit and measuring a preselected one of a parasitic resistance or a parasitic impedance of the ground connection, the indicator circuit of the transmitter coupled to the ground integrity testing circuit for indicating whether or not to the ground connection is of sufficient integrity;
a ground fault testing circuit coupled to the GROUND conductor and an energized one of the other conductors of the AC power branch circuit and operable to simulate a ground fault on the AC power branch circuit;
an arc fault testing circuit coupled between the HOT and NEUTRAL conductors of the AC power branch circuit and operable to simulate an arc fault on the AC power branch circuit; and
a signal generator for generating an identification signal on an energized one of the conductors of the AC power branch circuit for detection by a receiver positioned proximate to the AC power branch circuit but remote from the transmitter.
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25. A fault interrupter testing device, comprising:
- A user-actuable switch for creating a fault signal across a selected two of a plurality of conductors of an AC power branch circuit, the AC power branch circuit having connected thereto a fault interrupter;
a sensor coupled to the selected two of the plurality of conductors for sensing the fault signal;
a timer coupled to the sensor for timing the duration of the fault signal;
a comparator coupled to the timer for periodically comparing the duration of the fault signal to a predetermined stored value; and
an indicator coupled to the comparator and responsive to the comparator sensing that the duration has exceeded the stored value for indicating that the fault interrupter has not tripped the circuit within a time equal to the predetermined stored value.
- A user-actuable switch for creating a fault signal across a selected two of a plurality of conductors of an AC power branch circuit, the AC power branch circuit having connected thereto a fault interrupter;
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27. A method for transmitting an identification signal across an AC power distribution circuit, comprising the steps of:
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identifying an energized conductor and a return path conductor of an AC power distribution circuit, the energized conductor carrying an AC carrier signal; and
superimposing an identification signal on the AC carrier signal such that a period of repetition of the identification signal is greater than a period of the AC carrier signal.
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29. A method for determining the integrity of a ground connection in an AC power distribution circuit, comprising the steps of:
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connecting a ground integrity circuit to a GROUND terminal of the AC power distribution circuit;
using the ground integrity circuit, measuring the parasitic resistance between the GROUND terminal and earth ground; and
using an indicator circuit coupled to the ground integrity circuit to indicate whether the measured parasitic resistance exceeds a predetermined maximum.
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30. A method for determining the integrity of a ground connection in an AC power distribution circuit, comprising the steps of:
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connecting a ground integrity circuit to a GROUND terminal of the AC power distribution circuit;
generating a varying signal on the AC power distribution circuit;
using the ground integrity circuit, measuring a parasitic impedance between the GROUND terminal and earth ground by measuring a phase shift of the varying signal; and
using an indicator circuit coupled to the ground integrity circuit to indicate whether the measured parasitic impedance exceeds a predetermined maximum.
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31. A method of distinguishing a first AC power distribution circuit from others of a plurality of AC power distribution circuits including the first AC power distribution circuit, comprising the steps of:
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generating an identification signal on the first AC power distribution circuit from a first location;
at a second location remote from the first location, moving a mobile receiver to be adjacent a selected one of the plurality of AC power distribution circuits;
detecting a signal strength of the identification signal in the selected one of the AC power distribution circuits;
storing the detected signal strength;
moving the mobile receiver to be adjacent a second selected one of the plurality of AC power distribution circuits;
detecting a second signal strength of the identification signal as present in the second selected one of the AC power distribution circuits;
comparing the second signal strength to the stored signal strength;
if the second signal strength is greater than or equal to the stored signal strength, giving an indication thereof to a user;
if the second signal strength is greater than or equal to the stored signal strength, replacing the stored signal strength with the second signal strength; and
repeating said steps of detecting, comparing, indicating and replacing until the first AC power distribution circuit is identified.
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Specification