Device for measuring the intensity of an electric current and electric appliance including such device

An electric apparatus (10) supplied by at least two electric conductors (2), the apparatus comprising at least one measurement device (1) for measuring an intensity (I) of electric current in at least one of the electric conductors (2), the measurement device comprising at least one open magnetic circuit (3) defining at least two wide gaps (E), each of the gaps being closed by an electric coil (4), the magnetic circuit (3) and the electric coils (4) defining a closed path (C) for the circulation of a magnetic field, the electric coils (4) disposed in the gaps (E) being in the form of printed circuits (40) and comprising windings (41) engraved on a substrate, the windings (41) comprise a plurality of loops and each of the loops comprises an upper line (41a) and a lower line (41c) which are supported on opposite surfaces of the respective substrate, ends of the upper and the lower lines (41a, 41c) are coupled by return lines (41b, 41d) with one of the return lines (41d) coupling adjacent loops, portions of the upper and the lower lines (41a, 41c) of the loops extend parallel to each other and perpendicular to a direction of circulation of the magnetic field, and the coils (4) occupy more than one-third of the closed path (C), and the coils (4) each have the same number of windings, which are wound in opposite directions, and are electrically connected in a series such that their useful fields are increased and their parasitic fields are canceled.

A device (1) for measuring an intensity (I) of an electric current, the device comprising two magnetic plates (30) and two electric coils (4), the two magnetic plates (30) support opposite ends of the two electric coils (4) such that a first end of the electric coils (4) contacts one of the two magnetic plates (30) and a second end of the electric coils (4) contacts the other of the two magnetic plates (30), the two magnetic plates (30) are spaced from each other by the two electric coils (4) which define a gap (E) between the two magnetic plates (30), the two electric coils (4) supported by the two magnetic plates (30) such that the two electric coils are parallel to each other, each of the two electric coils (4) is made from a printed circuits (40) which comprise windings (41) engraved on a substrate, the windings (41) comprise a plurality of loops and each of the loops comprises an upper line (41a) and a lower line (41c) which are supported on opposite surfaces of the respective substrate, ends of the upper and the lower lines (41a, 41c) are coupled by return lines (41b, 41d) with one of the return lines (41d) coupling adjacent loops, the upper and the lower lines (41a, 41c) of the loops extend parallel to each other and parallel to each of the two magnetic plates (30), an electrical conductor (2) extends into the gap (E) centrally between each of the two magnetic plates (30) and the two electric coils (4) and parallel to the plurality of loops, a current, which is to be measured, passes through the electrical conductor (2) and induces a magnetic field around the electrical conductor (2) the two electric coils (4) deliver a voltage proportionate to a derivative of the intensity (I) of the current to be measured, and at least one module processes a voltage to determine the intensity to be measured, the two magnetic plates (30) and the two electric coils (4) define a closed path (C) for circulation of the magnetic field, and the two electric coils (4) disposed in the gaps (E) span more than one third of the closed path (C), the upper and the lower lines (41a, 41c) of the loops extend perpendicular to a direction in which the magnetic field circulates and the two electric coils (4) are electrically connected in a series, so that their useful fields are enhanced and their parasitic fields are canceled.