| 摘要 |
<p>PURPOSE:To improve an insulating characteristic, S/N and measurement accuracy by transmitting the light emitted from a single light emitting element through optical sensor heads disposed in parallel, then receiving the same with a single light receiving element. CONSTITUTION:The AC magnetic field generated by the current flowing in lines 20-1-20-3 is applied to Faraday elements 13-1-13-3 and the transmitted light by the effect thereof is polarized and modulated. The quantity of the light of 1/3 the light emitted from the light emitting element 11 is, therefore, supplied via light splitting means 23 to optical transmission paths 18-1-18-3. After the light past the optical sensor head 12-1 is subjected to intensity modulation, the light enters the light receiving element 21 after photosynthesis 24. The paths 18-1-18-3 are used to adjust the quantity of the incident light on the elements 13-1-13-3 in such a manner that said quantity attains equal. The incident light on the element 21 includes the AC component corresponding to zero phase current when abnormality or the like arises and the zero phase current flows to lines 19-1-19-3. The output of the element 21 is electrically converted in a converter 22 and the AC output is divided by the DC output, by which the error factor of the element 11 is removed.</p> |
