| 摘要 |
<p>PURPOSE:To detect a welding current with high accuracy by detecting a change of a space electron current as a change of the intensity of emitted light on the basis of the fluctuation of the magnetic field formed by the space electron current at a welding place. CONSTITUTION:A detection element 1 is arranged in such a state that the opti cal axis thereof becomes parallel to a magnetic field generated by an arc so as to correspond to the discharge gap 11 between a base material 9 and an electrode 10 constituted of a core or wire at the welding place of an arc welding apparatus and the plane of polarization of the light passing through the element 1 is rotated by the magnetic field excited by a generated arc. Therefore, since the magnetic field generated by the current change in the arc fluctuates, the angle of rotation of the plane of polarization of the light passing through the element 1 is changed by the fluctuation of the magnetic field and the voltage value outputted from a light detection means 3 changes corresponding to the current value in the arc and a welding current can be detected by detecting a welding magnetic field.</p> |
