In a simple electric motor the stator is made by permanent magnets and the rotor is a coil of enameled copper wire where an electric current flows. The coil supports angular acceleration and continues its spin to the left. https://www.mrosupply.com/v-belts/cogged-v-belts/bx-section/1251790_bx123_gates-rubber/ This torque persists until the coil poles reach the opposing poles of the stationary magnets (stator). The DC electric motor has its problems. He does not start. For the start to happen with complete confidence and in the right sense it is necessary that the brushes always emit current for the rotor and that no short circuit occurs between the plates due to the brushes. These can start by touching both plates. There is nothing to determine what the direction of your rotation in the match will be, either you can start by turning to the ‘left’ or the ‘right’.
The well-distributed attractions and repulsions are what make the rotor spin, although how such torques are obtained can vary among the various types of motors. The reversal of the direction of the current at the right moment is a necessary condition for the maintenance of the favorable torques, guaranteeing the operation of the motors.