In this type of electric motor, the permanent magnet is installed on a metal disk, affixed by a pin in an iron bearing. The magnetic flux formed by the permanent magnet passes through the series magnetic circuit generated by the permanent magnet, the air gaps and the iron plate.
When rotating the permanent magnet, the disc that is under the magnet also rotates. The disk follows the rotational movement of the permanent magnet, this occurs due to the circulation of induced currents. These currents are induced due to relative movement between the disc and the permanent magnet.
Induced currents tend to form, in accordance with Lenz’s law, a south magnetic pole on the disk under the rotating magnetic north pole of the permanent magnet, as well as a magnetic north pole on the disk under the rotating magnetic south pole of the permanent magnet.
While the magnet remains its movement relative to the disk, the induction of parasitic currents and magnetic poles with opposite polarities will continue. The disk thus rotates in the same direction as the permanent magnet, but must rotate at a slower speed to have a related speed between the metal disk and the permanent magnet.