The ideal transformer is one that works without loss. In the transformer in vacuum when applying the voltage U1 in the primary, with the secondary without load (open), the transformer absorbs an electric current of magnetization (Im).
As the circuit is inductive, the voltage U1 is advanced by 90 ° in relation to this current and the current Im generates the magnetic flux (φm) in the transformer core, which induces the counterelectromotive force (fcem) in the primary windings (e1) and secondary (e2).
For a transformer to increase the voltage, the number of turns of the secondary winding must be greater than that of the primary winding and for a transformer to lower the voltage, the number of windings of the secondary winding must be less than that of the primary winding.
In the operation of a transformer with secondary load when placing a load on the secondary, it will have a current I2 circling, delayed by an angle θ2 with respect to e2.
The current I2 generates a magnetomotive force f.m.m.m.2 and this force, consequently, deviate the equilibrium of the system reached as a function of the mutual flow φm, which was provided by f.m. produced (N1 · Im). Under these conditions, the transformer absorbs a high current such that the equilibrium between U1 and e1 is restored.
When referring to electric motors of the single-phase type, it is possible that because of the high frequency handling, in cases of cleaning, of the preventive maintenance of the connections, among other factors, the identification plates, may end up detaching from their terminals.
If the lack of identification is actually verified, it will not be feasible to carry out the connections at random, without taking any risks, such as possible damage to the engine. For the precise identification, as well as polarization of the coils or windings, it is necessary to make the individualization of the coils and the verification of the continuity of the two coils. H17296
It is worth noting that it is feasible to identify the auxiliary coil of the single-phase motor, and it is important to measure the resistance with the aid of a multi-tester, and can check the resistance value of each coil. Thus, single-phase motors have a specific number of terminals so that the connections that are necessary to make the best possible operation can be made.
When these engines are new, marketed directly from the factory or through authorized dealers, all of their terminals must show identification with sequences of letters or numbers.