Liaisons Electroniques-mecaniques Lem Sa

Lem Intellectual Property Sa

Secheron Sa

Marc Schaerrer

Wolfram Teppan

Pascal Morel

Pierre Cattaneo

Claudio Tricarico

Bernard Richard

Nicolas Venzin

A closed-loop current transducer for measuring a current (Ip) flowing in a primary conductor, the transducer powered by series connected voltage supplies (V_H, V_L) and comprising a magnetic field detector, a signal processing circuit including an amplifier circuit connected to the magnetic field detector, and a compensation coil (WS) connected to the amplifier circuit and configured to generate an opposing magnetic field seeking to cancel a magnetic field generated by the current flowing in the primary conductor. The amplifier circuit comprises a first switched mode power stage configured to drive the magnetic field generator, and a second switched mode power stage configured to balance the currents of the voltage supplies.

Closed-loop current transducer with switched mode amplifier

Sensor for measuring electrical parameters in a high voltage environment comprising a high voltage side () for connection to high voltage conductors, a low voltage side () for connection to low voltage power supply and measurement signal control circuitry, a measurement signal circuit (), and a power supply circuit (), and at least one isolating transformer () for transmission of electrical power supply and/or measurement signals between the low voltage side and the high voltage side. The isolating transformer comprises at least a first and a second transformer core (), a transformer coil () on a circuit board around a branch () of the transformer core on the high voltage side and a transformer coil () on a circuit board around a branch () of the transformer core on the low voltage side, the isolating transformer further comprising an intermediate coil () encircling at least one branch of each said at least two transformer cores.

Sensor for high voltage environment

An electrical current sensor comprises a magnetic circuit with an air-gap, a magnetic field sensor positioned in the air-gap, and a secondary coil surrounding a branch of the magnetic circuit. The magnetic circuit comprises at least two parts () that are assembled together, a branch portion () of each part being insertably received in a central cavity of the secondary coil in an axial direction (A). The air-gap () is arranged between overlapping branch portions of each magnetic field circuit part.

Current sensor

Growing community of inventors

Bernex, Switzerland

Marc Schaerrer