Under normal circumstances, the DC cooling fan can adjust the speed by adjusting the magnetic field and armature voltage.

Armature is the component that plays the key and pivotal effect in the process of the motor completes the transformation of mechanical energy and electrical energy.

For a generator, it is a component that generates electromotive force, such as the rotor in a DC generator, and the stator in an AC generator.

For a motor, it is a component that generates electromagnetic force.