Kabushiki Kaisha Meidensha

Tokyo Denryoku Kabushiki Kaisha

The Tokyo Electric Power Company, Incorporated

Tomoyoshi Ochiai

Takeshi Hayashi

Mituhiro Furuse

Shinichi Kuze

Ikuro Hirano

Apparatus for monitoring two sinusoidal electric quantities of a common period, comprises two similarly timed samplers, an arithmetic unit for combining, in accordance with a preselected relation, three consecutive samples of each electric quantity so as to produce an output signal which is independent of time and phase relations between the sampling pulses and the respective quantities. The output signal may be determined solely by peak values of the respective quantities, phase difference between the electric quantities, and timing period. The apparatus further comprises a discriminator circuit having a reference level and responsive to the output signal for producing a signal for use in monitoring the electric quantities.

Apparatus for monitoring two electric quantities by combining three

An instrument transformer being applicable for a current transformer and/or a voltage transformer which is comprised of a coil for developing magnetic field related to a primary current, the Hall element for generating the voltage in response to the magnetic field developed by the coil, a shield pipe for supporting and enclosing the Hall element, and a cone shaped insulating layer being laid between the coil and the shield pipe, enclosing the shield pipe.

Instrument transformer with cone-shaped insulating layer

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Tokyo, Japan

Tomoyoshi Ochiai