| 摘要 |
<p>PURPOSE:To eliminate the effect of an external magnetic field, by a method wherein a detecting coil for a current transformer is divided into plural sections, the divided coils are distributed onto a magnetic band through which main magnetic flux penetrates, and the detecting coils are connected in parallel and used. CONSTITUTION:Detecting coils 2-7 divided into plural sections are wound around a ring core 1, and homopolar sections S1-S6, F1-F6 in each coil are short-circuited-that is, they are connected in parallel. Penetrating flux phi1-phi3 from the outside intends to intrude into respective coil 2-7. Magnetic flux such as one phi2 penetrates into a loop formed by the coils 2, 3, but induced electromotive force is generated in each coil so as to deny magnetic flux phi2, and loop currents flow, thus generating magnetic flux, then denying intruding magnetic flux. Consequently, excess external magnetic flux does not penetrate into the core, and a current transformer is operated correctly. Accordingly, loop currents flow back only into sections among the coils, and do not flow out to leads 8, 9, thus preventing an effect on a current measured value.</p> |
