US 3,934,198 A · Multi-wire electronic kWh meter

Abstract

The metering of kilowatt hours in a single phase, three wire electrical system is accomplished by generating a first analog voltage which is representative of the voltage of the power consuming system. Second and third analog signals are generated which represent the current flowing through each of two of the three wires of the single phase power consuming system. The voltage representative analog signal is multiplied by each of the second and third current representative analog signals in either a direct pulse width amplitude multiplying network or in a feedback type pulse width amplitude time division multiplier network. A constant amplitude triangular generator is associated with the multiplier and the multiplier is implemented using C-MOS technology. The output modulated pulse signals from the multiplier are summed and converted in, for example, a low pass filter to a signal having an amplitude representative of the power in the power consuming system. An analog-to-pulse rate converter is used for converting the signal representing the average power to a series of output signals having a variable pulse repetition rate which is proportional to the average power, each output pulse signal representing a quantized amount of electrical energy. A stepping switch and register perform conventional accumulation, storage and display functions in response to the series of output pulse signals delivered thereto.

Claims14

Dependent claims

In an N wire, single phase power consuming system, an electronic kWh meter for metering electrical energy comprising

means for generating a first analog voltage representative of the voltage across the load impedance of said system,
means for generating N-1 analog signals representative of the current flowing through each of N-1 wires,
a multiplier means for simultaneously producing N-1 output signals representative of the product of said first analog voltage and each of said said N-1 current representative analog voltages, said product signals each being proportional to an instantaneous partial power consumed in said system,
means receiving said product signals for deriving signals proportional to the average partial power consumed in said system, and
means for summing said average partial power signals to derive the average power consumed in said N-wire single phase system.

2 more elements

In a three-wire, single phase, power consuming system, an electronic kWh meter for metering electrical energy comprising

means for generating a first analog voltage representative of the voltage across the load impedance of said system,
means for generating two analog signals representative of the current flowing through two wires of said three-wire system,
a multiplier means for simultaneously producing two output signals representative of the product of said first analog voltage and each of said two current representative analog voltages, said product signals each being proportional to an instantaneous partial power consumed in said system,
means receiving said product signals for deriving signals proportional to the average partial power consumed in said system, and
means for summing said average partial power signals to derive the average power consumed in said three wire, single phase system.

2 more elements

Dependencies are inferred from the claim text.

Multi-wire electronic kWh meter

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Multi-wire electronic kWh meter

Life of this patent

Abstract

Claims14