An arc spinner type interrupter has a stationary coil (101) coupled magnetically to a disk-shaped arc runner (103). A magnetic core (110 - 112) encases the coil (101) and has an annular gap (47) in Figure 7 extending across the upper exposed surface of the arc runner to permit access of an arc root to the arc runner (103). The magnetic core material (110 - 112) has high permeability at currents lower than the rated interrupting current of the device and the magnetic material saturates at higher current levels. The effect of the relatively high permeability saturable magnetic core (110 - 112) is to increase the transient recovery characteristics of the interrupter at low currents without having to increase the number of turns of the coil (101). The electrical coil (101) may be made of a spirally wound, relatively thin sheet of highly conductive material or can be made of a square conductor would in a coil form. The axial length of the coil is increased beyond that of prior art coils without substantially increasing the reluctance of the magnetic circuit. The electrical path (arrows 130) from the coil (101) to the arc runner (103) includes parts of the magnetic circuit (110 - 112).