Monthly Archives: abril 2018

The Magneto-Motive Force

The intensity of an inductive magnetic field (Magnetizing Force) H in a coil is subordinate to the intensity of the current flowing in a certain amount of turns. The higher the current, the stronger the magnetic field. In addition, the more turns, the more limited the field lines.

We can define FMM Magneto-Motive Force as the ratio of the flux production at the core of a magnetic circuit, analogously to the electro-motive force that flows from the electric charges in an electric circuit.

The cause is the magneto-motive force, similar to the electric voltage. The effect it causes is the magnetic flux, comparable to the flow of charges, electric current and the opposition to the effect is the magnetic reluctance, parallel to the electric resistance.

Through this verification, magnetic circuits or magnetic paths can be analyzed as electrical circuits. Despite the analogy between electric and magnetic circuits, it should be borne in mind that the magnetic flux φ is constituted in the nucleus by altering the atomic structure of the nucleus, because of the external pressure of the magneto-motive force (MMF) and is not a measure of the flow of charged particles, such as the electric current.

Rotor – Constructive Aspects

The rotor of an electric motor is made of the following parts:

– Axle: Made of steel, it transmits the mechanical power generated by the motor. It is designed thermally to correct problems such as warpage and fatigue;

– Field coils: Also called field winding, is made by a set of coils fed by direct current by the excitation system;      TPMSJ24ABSP

– Starting cage: It consists of bars and short-circuit rings, normally installed at the ends of the rotor poles or together with the field windings in the case of a smooth pole rotor. Used to break the engine by applying the same principles of asynchronous induction motors. It can be made of electrolytic copper or brass. During the nominal working regime it still has the function of attenuating sudden changes of load and transients in the network, helping to remain the motor in synchronism;

– Core: The rotor core can be made with laminated sheets or solid construction in a single steel block, there is no need for the plate properties to be identical to those of the stator, since there is only continuous current circulation in the rotor of permanent regime, which does not offer significant losses in iron.