Patent ID: 7256574

Claim:
A device for measuring an electric current, comprising: a sensor ( 3 ) positioned in an airgap of a core (N) of a transformer (B) and sensitive to a direction of a magnetic field prevailing in the airgap, the transformer, in use, having a first electric current (i 1 ) of a first magnetic field of a first direction generated by a primary winding ( 1 ) of the transformer, the transformer, in use, having the first electric current balanced by a second magnetic field of second direction opposite the first direction and generated by a secondary winding ( 2 ) of the transformer in which a second compensating current (i 2 ) flows, the magnetic field in the airgap being a field resulting from an addition of the first and second magnetic fields, the sensor ( 3 ) configured to regulate said compensating current (i 2 ) in closed loop mode by the sensor ( 3 ) sensing only a direction of said resultant magnetic field and controlling a reversal of a direction of circulation of the compensating current (i 2 ) in said secondary winding ( 2 ), the sensor being sensitive only to the direction of said resultant magnetic field, a measurement resistor (R m ) placed in series with the secondary winding ( 2 ) to obtain a value of the first current (i 1 ) through a measurement of the second compensating current (i 2 ), and a temperature correction element ( 10 ) for the circuit of said secondary winding ( 2 ), the temperature correction element being connected in series with the measurement resistor.