Apparatus for providing cost efficient power measurement
First Claim
1. Apparatus for measuring electrical power consumed in an electrical system comprising:
- means for generating at least a first signal representing an ac voltage provided to said system and at least a second signal representing an ac current provided to said system;
first multiplexor means responsive to said first signal and said second signal, said first and second signals appearing at the output of said first multiplexor means in a controlled sequence;
first means coupled to the output of said first multiplexor means for converting the controlled sequence signals at said multiplexor output to corresponding dc signals;
second means coupled to said first converting means for converting said dc signals to digital signals; and
means responsive to said digital signals for providing a third signals representing the product of said first and second signals, said third signal representing the apparent power provided to said system by said ac current and voltage signals.
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Accused Products
Abstract
Power measuring apparatus including a first multiplexor having its inputs responsive to the polyphase voltage and current inputs being measured. The multiplexor reads these inputs in sequence based on address signals provided by a program controlled microprocessor. The output of the multiplexor is coupled to an RMS to DC converter, the output of which is coupled to a second multiplexor. The voltage inputs are coupled to a voltage averaging device, the output thereof being coupled to additional inputs of the second multiplexor, the output of the second multiplexor being coupled to the microprocessor via an analog to digital converter. The microprocessor reads and compares the voltage output from the averaging circuit and the corresponding voltage at the output of the converter and generates a correction factor and responds thereto. The microprocessor to periodically adjusts the digital value of the voltage from the averaging circuit in response to the correction factor, the adjusted signal being coupled to display means for visual readout.
A third multiplexor is provided to detect polyphase voltages and currents. The outputs of the third multiplexor are coupled under the control of the microprocessor to an analog multiplier in a time shared manner via voltage and currents scaling devices such that each phase voltage and corresponding current is simultaneously coupled to the multiplier. The output of the multiplier is coupled to a low pass filter, the output of which corresponds to the kilowatt power consumed for that phase. The microprocessor is capable of calculating a system power factor.
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Citations
36 Claims
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1. Apparatus for measuring electrical power consumed in an electrical system comprising:
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means for generating at least a first signal representing an ac voltage provided to said system and at least a second signal representing an ac current provided to said system; first multiplexor means responsive to said first signal and said second signal, said first and second signals appearing at the output of said first multiplexor means in a controlled sequence; first means coupled to the output of said first multiplexor means for converting the controlled sequence signals at said multiplexor output to corresponding dc signals; second means coupled to said first converting means for converting said dc signals to digital signals; and means responsive to said digital signals for providing a third signals representing the product of said first and second signals, said third signal representing the apparent power provided to said system by said ac current and voltage signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. Apparatus for measuring electrical power consumed in a polyphase electrical system comprising:
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means for generating first, second and third analog signals representing ac voltages and fourth, fifth and sixth analog signals representing ac currents; first multiplexor means responsive to said first, second and third analog signals representing ac voltages provided to said system and to said fourth, fifth and sixth analog signals representing ac currents provided to said system, all said analog signals appearing at the output of said first multiplexor means in a controlled sequence; first means coupled to the output of said first multiplexor means for converting the signals at said multiplexor output to dc signals, second means coupled to said first converting means for converting said analog signals to corresponding digital signals; and means responsive to said digital signals for providing a seventh signal representing a sum of products of said first and fourth analog signals, said second and fifth analog signals and said third and sixth analog signals, said seventh analog signal representing the apparent power consumed by said system. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. Apparatus for measuring the instantaneous electrical power consumed in a polyphase electrical system comprising:
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means for providing first, second and third analog signals representing instantaneous ac voltage and fourth, fifth and sixth signals representing instantaneous current signals supplied to said system; multiplexor means responsive to said analog signals; processor means for controlling the sequential input scanning of said multiplexor means; multiplier means coupled to the output of said multiplexor means for generating in sequence analog signals representing the instantaneous product of said first and fourth, said second and fifth, and said third and sixth analog signals; filter means coupled to said multiplier means and responsive to said sequential analog signals; and means for coupling the output of said filter means to said processor means, the analog product signals being summed by said processor means to provide a signal representing the actual power being consumed in said system. - View Dependent Claims (34, 35, 36)
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Specification