Two carbon brushes in a rigging are used in the commutator. Frame is of the round type, exposed on both sides of the armature shaft. Four binding post terminals are on top of the frame. Reference: The ...

The brushed DC motor is the oldest electric motor type still in use today. First invented in the 1870s, brushed DC motors rely on two sets of opposing permanent magnets - a rotor and a stator.

The other major type of electric motors are brushless. Rather than use a commutator to switch the direction of current, magnetic-field shifting is done entirely without physical contacts.