| 摘要 |
1,194,982. Current measurement. MERLIN GERIN. Jan. 11, 1968 [Jan. 18, 1967], No.1584/68. Headings G1A and G1U. In apparatus for measuring current in a high voltage line 13, the current is passed through a winding 17 to control the magneto-optic body 16 of a Faraday effect device so as to rotate the plane of polarization of a polarized light beam P passing therethrough, the rotated beam being immediately passed to an analyzer 100 which converts it to a beam whose intensity is related to the degree of rotation of the plane of polarization. The beam is transmiteed to a low voltage measuring station where it is passed through a polarizer 101 set to the same angle as the analyzer 100. The light beam from the polarizer is then passed through the magneto-optic body 18 of a second Faraday device to an analyzer 20. The amplitude of the signal derived from the analyzer 20 is detected by photo-cell 21 and used to control a balancing device 24 and amplifier 25 to provide an electric signal which is passed to winding 19 around the body 18 to produce that degree of rotation of the light beam, corresponding to the rotation produced by the current to be measured in the magneto-optic body 17, which reduces the output of analyzer 20 to a given, near zero value. The amplitude of the controlled signal, which represents the current in the conductor 13 is measured at the load 26. The system eliminates the possibility of errors due to polarization distortion which might occur in a polarized beam passing along the long path between the high and low voltage parts of the system. |
