| 摘要 |
<p>PURPOSE:To sharply improve the zero-phase current detecting sensitivity by shielding the circumference of a magnetic core provided with a gap section with a magnetic shielding member and providing an magneto-optical sensor to the gap section. CONSTITUTION:By shielding a magnetic core 1 with a magnetic shielding member 4 made of a magnetic material which is high in magnetic permeability, fluctuation of the zero-phase magnetic field at the gap section 3 of the magnetic core 1 caused by a magnetic flux induced in the magnetic core 1 by three-phase positive current is eliminated. Moreover, by detecting a zero-phase magnetic field, namely, zero-phase current by means of a noninductive magneto-optical sensor 5, the detecting sensitivity can be improved sharply.</p> |
