Siemens Aktiengesellschaft

Gunter Steinmuller

Manfred Schwendtner

Julius Brunner

Wolfgang Dohmstreich

Reinhard Stark

The current transformer of an electronic house-service meter has a ferromagnetic core which, except for an air gap, is closed. A measuring coil is inserted in the air gap and is fastened, and dimensioned so that it lies within the cross sectional area of the core.

Current-voltage transformer for electronic house-service meter

An electronic arrangement for determination of reactive power, including two transducers delivering at their outputs measuring voltages proportional to supply current and supply voltage. An additional phase shift of 90.degree. between the two measuring voltages is produced by phase-shifting elements. A signal proportional to reactive power is produced in a following multiplier element. To preclude as far as possible variation of amplitude and phase shift occurring on frequency fluctuation in a frequency range close to rated frequency of the power supply, an all-pass is connected as a phase-shifting element ahead of each of the two respective inputs of the multiplier element whereby one all-pass is designed to produce a phase shift of +45.degree. and the other all-pass is designed to produce a phase shift of -45.degree. at the rated frequency of the power supply.

Electronic arrangement for determination of reactive power

An electronic multiphase watt-hour metering system containing time-division multiplying circuitry. A duty cycle modulator and a switching device are provided for each phase of interest, the output signals of which are combined and conducted to a current-to-frequency converter. The output frequency of the current-to-frequency converter is responsive to the rate of electrical power consumption from a multiphase transmission system. In one embodiment, the current-to-frequency converter is coupled at its output to an accumulating counting system for recording the total energy supplied to a load. There may further be provided an indicator responsive to the frequency of the current-to-frequency converter for providing a visual indication of the instantaneous rate of power usage.

Electronic three-phase watt-hour meter

An apparatus for measuring the electric power or energy in an a-c network is disclosed wherein a multiplying device operating according to the principle of pulse duration-pulse height modulation is used and the variables proportional to the load current and the load voltage are taken directly from the load current and the load voltage respectively.

Apparatus for measuring the electric power or energy in an A-C network

In a measuring device for integral values formed over a time span which is constantly up-dated, the system being one in which pulses represent a fixed quantity of the value being measured, the pulses are stored in a random access memory of a microcomputer with the central processing unit of the microcomputer sequentially addressing individual memory cells, in a repetitive manner after each sweep of the time span.

Measuring device for integral values formed over a time span

This invention is an electronic kilowatthour meter with a time-division multiplier, wherein a proportional first current is derived from the load voltage without a voltage transformer and a proportional second current is derived by means of an inverting amplifier, with a polarity opposite to that of the first current and instantaneous values halved as compared to the first current, and that the first current is added to the second current in one of two switching conditions by means of a switch which is operated by a pulse width-frequency modulator controlled by the load current, so that the average value of the sum current is proportional to the product of the load current and the load voltage.

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Nuremberg, Germany

Gunter Steinmuller