Electromagnetic trip device for an electric switch apparatus, electric switch apparatus comprising one such trip device

An electromagnetic trip device for an electric switch apparatus, comprising a magnetic circuit formed by a shell, a fixed core and a moving core sliding due to the action of a coil, the moving core having a radial crown separating a first part and a second part of different radial cross-sections, the shell comprising a radial surface having an opening through which the first part of the moving core passes, superposition of the radial crown of the moving core and the radial surface of the shell forming, in a rest position, a magnetic flux transfer surface enabling flow of an axial magnetic flux, comprising intercalary adjustment means of said flux transfer surface positioned between the moving core and the radial surface of the shell, said intercalary adjustment means comprising two calibrated elements adjoined surface against surface and being respectively formed by an alternation of magnetic sectors and non-magnetic sectors, movement of a first calibrated element with respect to a second calibrated element enabling variation of the magnetic flux transfer surface to be obtained.