TRANSFORMERS 

Introduction

Once acquired the concept of electromagnetic induction and, consequently, that one of transformer, meant as simplest of it blots of it static electrical workers, the reader must hour to learn to distinguish the various outgoing conductors, is from the primary winding that from that secondary one, with which it is sometimes necessary to realize some connections of adaptation, applying obviously sure elements of calculation. That they are not those that concur to plan and to construct a transformer, because the facility with which today this can be find in commerce member does not encourage of sure the amateur to undertake a task much hard, but that, much more simply, they allow than to bring some modification to the values of the voltages available, waves to derive of others, new and various, necessary for a particular system of feeding. It has been already said that every transformer is constituted from at least two windings, electrically separates to you between they; in one of these it is made to slide the current, as an example that one provoked from a take-light, the other captures the voltage that is wanted to be used. Which normally introduces a reduced value regarding what it characterizes the voltage applied to the primary winding, attributing to the machine static electrical worker the qualification of "transformer in reduction", in order to indicate that in it verification a transformation of voltage from a higher value to one more bottom and that distinguishes it from the "transformer in climb", in which the voltage, applied to the primary winding, is transformed more in values elevates to you on that secondary one. These second types of transformers, moreover, can only interest one minority of practical hobbyist applications.

COMPOSITION OF THE TRANSFORMER

Every transformer is composed from at least two windings and in this case the symbol electrical worker, than it represents it theoretically, is that one brought back in figure 1.

Fig. 1 - The transformer, in its simpler expression, is composed from at least two windings elettricamente isolates  between they: the head physician and the secondary one. The sbarrette vertical, designed between the two windings, symbolize the ferromagnetic nucleus, on which, in practical, the threads are bundled up conductors.

The  vertical lines, designed between two solenoids, symbolize the ferromagnetic nucleus on which, in practical, the windings with enameled thread of branch are made up. More just, the matassine of thread conductor come realized on a cartoccio, that it assumes the function of support of the wrapped thread of branch; the cartoccio it comes then inserted on the laminated iron nucleus, formed from a latten package of iron to the silicon, like indicated in "the exploded" design in of figure 2.

Fig. 2 - "exploded" sight in of a typical transformer composed from two windings. The function of the serrapacco is that one to maintain the package pressato to lamellare of the ferromagnetic nucleus, represented from a sure number of lattens to the iron-silicon, that they can es­sere various constructed.

Fig. 3 - For section of the nucleus of a transformer in­tende the surface, expressed in square millimeters or squared centimeters, of the section of the  central column of the package to lamellare, that is that one indicated in the design.

The windings, that they can more be two or than two, are overlapped or place side by side to you, but always it isolates to you electrically between they. That means that the primary winding does not have to never find in contact electrical worker with that secondary one. Of usual, the primary winding is represented from an elevated number more than coils, that it can vary between the little hundreds, the migliaia and beyond. Larger it is the voltage applied to the head physician, plus elevated is the coil number with which this it is constructed. We make an example: if for the voltage of 110 V 560 coils are necessary, for that one of 220 V they serve more than 1.000 coils. 11 diameter of the enameled thread of branch instead depends on the intensity of current that is wanted to be made to slide in the head physician.

The number of coils, that compose the secondary winding of the transformer, is proportional to that one of coils of the primary winding and is conditioned from the value of the voltage that is wanted to be obtained.