CURRENT MEASURING DEVICE Russian patent published in 2018 - IPC G01R15/24 

FIELD: measuring equipment.

SUBSTANCE: invention relates to an apparatus for measuring an electric current using a Faraday effect and in particular to a reflective device for measuring electric current, in which light falls on one end of the optical fiber for the sensor and is reflected from its other end. Claimed current measuring device is configured to include at least light entrance and exit, an optical fiber for a sensor, a Faraday rotator, a first 1/4 wavelength plate, a second 1/4 wavelength plate, a polarization separator, a light source and a signal processing circuit, comprising a photoelectric conversion element. Optical fiber for a sensor has birefringence and comprises one end into which two circularly polarized light beams, having different directions of rotation, are introduced, and the other end, which reflects the introduced circularly polarized light beams. In addition, the phase difference of two linearly polarized light beams is compensated in the round-trip light between the two 1/4 wavelength plates and the Faraday rotation angle, and the Faraday rotator is magnetically saturated, it is set to 22.5 + α°, so that the fluctuation range for the ratio error in the measured value of the current to be measured is set within ±0.5 %. In addition, the crystal axes on the optical faces of the two 1/4 wavelength plates are set to be perpendicular or set to be in the same direction. Technical result is the obtaining of a fluctuation range of the relative error in output, reliably kept within the limits ±0.5 %, as well as simplification of assembly.

EFFECT: technical result is the obtaining of a fluctuation range of the relative error in output, as well as simplification of assembly.

12 cl, 31 dwg, 5 tbl