CONTACT-FREE CURRENT METRE Russian patent published in 2009 - IPC G01R15/00 

FIELD: electricity.

SUBSTANCE: contact-free current metre comprising secondary winding (1) of current transformer, generator (2) and receiver (5) of magnetic flux, optoelectronic converter (8) and measurement (9), relay protection and automatics devices. Generator (2) and receiver (5) of magnetic flow are arranged in the form of coaxially installed cylindrical induction coils. Induction coil of magnetic flux generator (2) is connected to the secondary winding of (1) current transformer, and induction coil of magnetic flux receiver (5) is connected via optoelectronic converter (8) to measurement (9), relay protection and automatics devices. In order to reduce magnetic flux of dispersion, not engaged with induction coil of magnetic flux receiver (5), with preservation of device size and its reliable operation, induction coil of magnetic flux generator (2) and receiver (5) are equipped with magnetic flux concentrators (3, 6) that are coaxial with them and identical in shape, accordingly. Each of magnetic flux concentrators (3, 6) is made of material with high magnetic permeability, has cylindrical part installed in cavity of according induction coil, and outside of it - external part, cylindrical section of which is located on the side of induction coil, is aligned with section in the form of truncated cone along its larger base and is made with D diametre not less than external diametre d of induction coil. External parts of magnetic flow concentrators (3, 6) by smaller bases of truncated cones, on which, coaxially to magnetic flow concentrators (3, 6) there are axisymmetric electrostatic screens fixed (4, 7), made of non-magnetic material, are inverted to each other.

EFFECT: higher accuracy of measurement due to reduction of losses of magnetic flux that induces current in induction coil of magnetic flux receiver.

1 dwg