| 摘要 |
PURPOSE:To suppress the generation of leaked magnetic flux of an energizing coil, and to reduce a rise time of an energizing current, by providing a leaked magnetic flux suppressing means of the energizing coil, which is provided between a magnetic pole and a feedback magnetic path body, and is constituted of a nonmagnetic conductive material for surrounding a part of the outside circumference of the energizing coil without forming a closed circuit for surrounding the whole outside circumference of the energizing coil. CONSTITUTION:A block 7 for suppressing a leaked magnetic flux phiL of an energizing coil 4 is provided between a magnetic pole 3 and a feedback magnetic path body 6. The block 7 is constituted of a nonmagnetic and conductive material and surrounds the greater part of the outside circumference of the energizing coil 4, but does not form a closed circuit for surrounding the whole outside circumference of the energizing coil because it has a cut part 8. The suppressing body 7 is cut by at least one piece so that the closed circuit running along the outside circumference of the energizing coil 4 is not constituted, therefore, it has no effect for reducing a main magnetic flux phiM. That is to say, since it can reduce an hourly variation of the main magnetic flux phiM in a sampling time ts, it can reduce an electromagnetic induced noise containing in a signal fetched from an electrode 5. |
