The operating principle behind permanent magnet DC machines is quite simple. There is a stator and a rotor. The stator is stationary, in most cases it is the outer shell of the motor assembly and envelopes the rotor, which is inside. For permanent magnet machines that is always the case. The stator has three windings, referred to as the phase windings, which could have one, two, or more pairs of poles. If it is a one pole pair motor, then there would be a south and a north pole for that winding. The rotor is made up of permanent magnet material, which is mined from the Earth. For a one pole pair machine, one full electrical cycle is equal to one mechanical rotation as seen in the diagram shown on the bottom. One electrical cycle is actually six steps. Each winding has two poles: so in this case, pole 1 and 4 would be for one winding, pole 2 and 5 would be for another winding, pole 3 and 6 would be for the third winding. The magnet will align itself based on the magnetic field and will therefore rotate. To achieve continuous rotation of the permanent magnet rotor inside, the magnetic field on these windings has to change via commutation. For simplicity and to describe six-step drive mode, assume the engineer is talking about a single pole pair motor.