DC generator working principle
The working principle of the DC generator is to induce the alternating electromotive force in the armature coil.
By the commutator and the commutation of the brush, it becomes the principle of DC electromotive force when it is taken out from the brush end.
The direction of the induced electromotive force is determined according to the right-hand rule (the magnetic line is pointing to the palm of the hand, the thumb is pointing to the direction of movement of the conductor, and the other four fingers are pointing in the direction of the induced electromotive force in the conductor).
How does a DC motor work?
The direction of the conductor's force is determined by the left-hand rule. This pair of electromagnetic forces forms a moment acting on the armature. This torque is called electromagnetic torque in the rotating machine. The direction of the torque is counterclockwise, in an attempt to rotate the armature counterclockwise. If this electromagnetic torque can overcome the resistive torque on the armature (such as the resistive torque caused by friction and other load torque), the armature can be rotated counterclockwise.