ABB has implemented this technology in the field of contactors on

the basis of experience gained in the field of circuit-breakers with

magnetic drive.

The magnetic drive adapts perfectly to this type of apparatus thanks

to its precise and linear travel.

The drive, which is of bistable type, is fitted with an opening and a closing coil.

The two coils – individually energised – allow the drive mobile armature

to be moved from one of the two stable positions to the other.

The drive shaft is solid with the mobile armature and held in position

in a field generated by two permanent magnets (fig. A).

Energising the coil opposite to the magnetic latching position (fig.

A) of the core, the magnetic field is generated (fig. B), which attracts

and moves the mobile armature into the opposite position (fig. C).

Every opening and closing operation creates a magnetic field

concordant with the one generated by the permanent magnets, with

the advantage of keeping the intensity of the field itself constant

during service, regardless of the number of operations carried out.