Matsushita Electric Works, Ltd.

Akimi Shiokawa

Kazunari Yoshimura

Yasuo Ichimura

Yoichi Kunimoto

Eiji Iwami

Akihiro Ishibashi

Yasuo Itimura

The AC detection coil is a toroidal coil and includes plural radial-line conductors which are formed on a front face and a rear face of a substrate, conductive connection parts and conductive through-holes which connect electrically each end of radial-line conductors, wherein plural winding turns are consecutively formed by a connection of each radial-line conductor on the front and the rear faces, respectively, and include a forward coil and a backward coil, and each shape on the front and the rear faces of the radial-line conductors and the conductive connection parts are identical with each other. Consequently, when seen from a thickness direction of the substrate, areas of the forward coil and the backward coil are equal to each other, and an external, unneeded to be detected, magnetic field can be canceled each other by the forward coil and the backward coil, then a current detection accuracy can be improved.

Alternating current detection coil

An abnormal current discriminating method including an arc current detecting method and the apparatus for performing the same in which the arc current method includes the steps of: extracting a predetermined transition pattern specified by the combination of fluctuation patterns of peak values of three continuous half waves from the peak value for each half wave detected from an alternating current flowing to the AC load circuit which is sampled in a predetermined cycle and converted into a digital value, counting the number of appearances of the predetermined transition pattern, and comparing the count value with a predetermined threshold. According to which, a series arc which may be caused in a relative small current range by an apparatus cord or the like which has not been detected by an instantaneous breaker and an arc short-circuit phenomenon generated together with an arc through the contact between the cores in a cord and an interior wiring can be detected by executing simple algorithm without error detecting.

Method for discriminating abnormal current including arc current in AC load circuit and apparatus for executing the same

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Osaka, Japan

Akimi Shiokawa