Current transducer for measuring an electrical current flowing through a cable

摘要

The present invention concerns current transducers for measuring a current flowing through a cable (4). The current transducers have a ferromagnetic core (1) providing a substantially ring-shaped portion (21) and at least two legs (12). The ring-shaped portion (21) has one air gap (2) or two air gaps. A magnetic field sensor (3) is placed in or at each of the air gap(s). The ring-shaped portion (21) forms a magnetic circuit that encloses the cable (4) and guides the magnetic field generated by current to the air gap(s) (2). Each leg (12) extends from the center of the associated magnetic field sensor (3) in a direction that runs perpendicularly to the longitudinal axis of the cable (4) and has a certain length (A). The length (A) of the legs (12) is designed so long that at least two magnetic paths are formed which guide a component of an external magnetic field which extends in the direction of the legs (12) around the magnetic field sensor(s) (3).