Electric motor



The armature is the part of an electric machine, magnetically coupled to the inductor, where an electromotive force is generated by induction.

The armature is the rotor in DC machines and the stator in synchronous AC machines.

The term induced term varies depending on the context in which it is used. It is usually linked to the electricity sector, electric machines and motors.

Electric machines and motors

If we are talking about electric machines and electric motors. In this context the armature is the part of the rotating machine where the transformation of electrical energy into mechanical energy occurs by electromagnetic induction.

In DC electric motors, the armature is the rotating part. The rotating part of these electric motors is formed by a drum constructed of silicon iron stacked plates of 0.5 mm thickness with a series of longitudinal grooves in its periphery. Inside these grooves are lodged the coils where the electromotive force is induced when it rotates within the magnetic field created by the inductor.

The ends of the coils are connected to the deltas (copper sheets) arranged on the periphery of the collector (insulating cylinder). The collector is in charge of connecting the coils with the external circuit of the machine by means of static carbon brushes that rub on the delgas.

The armature in the alternators

In the alternators, the armature is the fixed part of the machine. In this case the armature is formed by a hollow cylinder of stacked sheets of silicon steel with slots in the inner part, where the coils are housed. In these coils the electromotive force is induced when the inductor rotates inside the armature.

The armature coils are connected to terminals that are outside the housing of the machine in order to connect them to the external circuit to which they deliver the induced current.


Published: November 30, 2017
Last review: November 30, 2017