Abstract: An arrangement for converting a multiphase electric signal into a frequency is disclosed. Illustratively, the arrangement comprises an adder circuit for adding the individual phases comprising said multiphase signal. The arrangement also comprises one first polarity reversing switch for each phase in the multiphase signal. A voltage/current converter is connected downstream of the first polarity reversing switches. At least one second polarity reversing switch is connected downstream of the voltage/current converter. A control circuit generates a periodic switch-over signal for controlling the first and second polarity reversing switches. In addition, a constant current source is connected to an input of the second polarity reversing switch.

Abstract: A circuit arrangement for summing power outputs is disclosed. The circuit arrangement is especially useful in connection with a multi-phase electricity meter. The arrangement includes a plurality of input circuits connected in sequence, each of which has a current-to-voltage converter and a multiplier connected to the current-to-voltage converter. A voltage-to-frequency converter is connected at the output of each multiplier. Starting, at least with the second input circuit in the sequence, an adder is connected to the voltage-to-frequency converter by means of two inputs of the adder. Two other inputs of the adder are connected to two outputs of the preceding input circuit in the sequence. Illustratively, two outputs of each adder form two outputs of the corresponding input circuit. A ternary encoder followed by a ternary decoder may be located between the outputs of one input circuit and the adder of the succeeding input circuit.

Abstract: A measuring transformer comprises a ferromagnetic core having a central branch. The central branch comprises at least one unit that is surrounded in part by an electrical conductor in the form of a U. Each unit of the central branch of the core has two outer air gaps and one or more central air gaps. Each outer air gap has length, that when measured in the longitudinal direction of the unit, is longer than the sum of the lengths of the one or more central air gaps. At least one magnetic sensor is contained in a central air gap of each unit and the central branch includes a total of at least two magnetic sensors. The measuring transformer is especially well suited for use in multifunction measuring instruments.

Abstract: A circuit arrangement for finding a sum of electrical power outputs for use in a multi-phase electricity meter is disclosed. The circuit arrangement comprises a plurality of multiplier circuits arranged in sequence. The sequence of multiplier circuits has two poles which form the output poles of the circuit arrangement. Each multiplier circuit comprises a Hall element, an amplifier, and a polarity reversing switch.