| 摘要 |
<p>PURPOSE:To accurately measure a conductor current of power cable consisting of a metal, sheath and cable conductor by providing a photomagnetic field sensor utilizing Faraday effect so that the sensitivity direction is coincident with a circumferential direction of the cable. CONSTITUTION:The power cable consists of the cable conductor 1 inside and the cable sheath 2 to which a general junction box 3 for grounding is provided at the metallic outer jacket. At the lower side of this junction box 3, a grounding terminal 4 is provided, from which a grounding current K is made to flow through a grounding line 5, while the conductor current I is made to flow in the conductor 1. Then the photomagnetic field sensor 6 utilizing Faraday effect is arranged so that the sensitivity direction is coincident with a circumferential direction of the cable, at the position making an angle of 30-90 deg. with the terminal 4 and on the surface W which is at a distance shorter than (a) away from a center surface S including the terminal 4 vertical to the cable in the junction box 3 to the direction of the cable axis and is parallel to the surface S, when a sheath radius of the junction box 3 is expressed as (a).</p> |
