Electrical fault detecting device
First Claim
1. Apparatus for continuously detecting illegal tampering with an electricity meter which is adapted to record the amount of electricity supplied to said meter through cables, the apparatus comprising:
- a first signal generating means, situated externally of and upstream of said meter and adapted to generate a first signal which is representative of the current flowing through one of said cables at a location outside said meter, in the vicinity of the first signal generating means;
a second signal generating means, situated within said metering device, and adapted to generate a second signal which is representative of the amount of electricity to be recorded by said meter; and
a monitoring means adapted to monitor the first and second signals and to produce a third actuation signal when one of the first and second signals differs from its correct value as a result of tampering.
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Accused Products
Abstract
An apparatus for detecting illegal tampering with an electricity meter which is adapted to record the amount of electricity supplied to the meter through cables has a first signal generating sensing coil situated externally of, and upstream of, the meter which generates a first signal representative of the current flowing through one of the supply cables and a second signal generating second sensing coil, located within the meter, which generates a second signal representative of the amount of electricity to be recorded by the meter. A Monitoring device monitors the first and second signals and produces a third actuation signal when one of the first and second signals differs from its correct value as a result of tampering.
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Citations
29 Claims
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1. Apparatus for continuously detecting illegal tampering with an electricity meter which is adapted to record the amount of electricity supplied to said meter through cables, the apparatus comprising:
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a first signal generating means, situated externally of and upstream of said meter and adapted to generate a first signal which is representative of the current flowing through one of said cables at a location outside said meter, in the vicinity of the first signal generating means; a second signal generating means, situated within said metering device, and adapted to generate a second signal which is representative of the amount of electricity to be recorded by said meter; and a monitoring means adapted to monitor the first and second signals and to produce a third actuation signal when one of the first and second signals differs from its correct value as a result of tampering. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An electricity meter adapted to record the amount of electricity supplied to it through cables, fitted with apparatus for detecting illegal tampering comprising:
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a first signal generating means, situated externally of and upstream of said meter and adapted to generate a first signal which is representative of the current flowing through one of said cables at a location outside said meter in the vicinity of the first signal generating means; a second signal generating means, situated within said metering device, and adapted to generate a second signal which is representative of the amount of electricity to be recorded by said meter; and a monitoring means adapted to monitor the first and second signals and to produce a third actuation signal when one of the first and second signals differs from its correct value as a result of tampering. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An electricity meter which is adapted to record the amount of electricity supplied to said meter through input cables, fitted with an apparatus for detecting illegal tampering comprising:
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a first coil disposed externally of and upstream of said metering device and in relation to one of said input cables so as to have induced therein a first electrical signal upon passage of current through the cable; a second coil disposed within said metering device and in relation to one of said input cables so as to have induced therein a second electrical signal upon passage of current through the cable; comparator means for comparing said first and second electrical signals; and indicator means actuable by an imbalance of said first and second signals.
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27. An electricity meter of the type having a meter disc whose rotational speed varies with the current fed to it through input cables, fitted with apparatus for detecting illegal tampering comprising:
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a sensing coil located externally of and upstream of said metering device and in relation to one of said input cables so as to have induced therein a signal which varies with the passage of current through the cable; detecting means located within the metering device adapted to produce a signal resulting from the rotation of said meter disc which varies with the rotational speed of the disc; tamper indicating means; and actuating means for actuating the tamper indicating means, the signals from the coil and from the detecting means acting in opposite senses on the actuating means to render it inoperative under correct operating conditions, but to operate it and actuate the tamper indicating means when the signal received from the detecting means is insufficient to counteract the effect on the actuating means of the signal from the coil.
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28. Apparatus for continuously detecting tampering with an alternating current electricity supply fed through input cables to a metering device, comprising:
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a first coil disposed externally of and upstream of said metering device and in relation to one of and upstream of said input cables so as to have induced therein a first electrical signal upon passage of current through the cable; a second coil disposed within said metering device and in relation to one of said input cables so as to have induced therein a second electrical signal upon passage of current through the cable; comparator means for comparing the first and second electrical signals; and indicator means actuable by an imbalance of said first and second signals.
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29. Apparatus for continuously detecting tampering with an alternating current electricity supply fed through cables to a metering device of the type having a meter disc whose rotational speed varies with the current fed to the metering device, comprising:
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a sensing coil located externally of and upstream of said metering device and in relation to one of said input cables so as to have induced therein a signal which varies with the passage of current through the cable, detecting means located within the metering device adapted to produce a signal resulting from the rotation of the said disc which varies with the rotational speed of the disc; tamper indicating means; and actuating means for actuating the tamper indicating means, the signals from the coil and from the detecting means acting on the actuating means to render it inoperative under correct operating conditions, but to operate it and actuate the tamper detecting means when the signal received from the detecting means is insufficient to counteract the effect on the actuating means of the signal from the coil.
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Specification