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It is indeed a very useful device. This allows us to easily multiply or divide the voltage and current in the AC circuits. In fact, the transformer has made remote transmission of electrical energy a practical reality, as AC voltage can be “increased” and current “graduated” to reduce power losses from wire resistance along power lines that connect power plants to loads. At both ends (generator and loads), transformers reduce voltage levels to ensure safer operation and more cost-effective equipment. Another similar technique to minimize eddy current losses, which is best suited for high-frequency applications, is to make the core from iron powder instead of thin sheets of iron. Like rolling boards, these iron granules are individually covered with an electrically insulating material, which means that the core is non-conductive, except for the width of each pellet. Powdered iron cores are often found in transformers that process high-frequency currents. A transformer is a device that can change the size of an alternating current or alternating voltage. The main advantage of an autotransformer is that the same supercharging or buckling function is achieved with a single winding, making it cheaper and easier to manufacture than a normal transformer (insulator) with primary and secondary windings. However, before using any form of transformer with an electrical device, be sure to check the power. Laminate cores like the one shown here are standard in almost all low-frequency transformers. Remember the photo of the transformer cut in half that the iron core was made of many thin sheets and not a solid piece. Eddy current losses increase with frequency, so transformers designed to operate at a higher frequency power (e.B 400 Hz used in many military and aeronautical applications) must use thinner laminations to reduce losses to a respectable minimum.

This has the undesirable effect of increasing the manufacturing costs of the transformer. Closely related to the subject of flow containment is the leckinduktivität. Since leckinduktivity corresponds to an inductance connected in series to the winding of the transformer, it is manifested by a mass impedance with the load. The more current is absorbed by the load, the less voltage is available at the secondary winding terminals. Usually, good voltage regulation is desirable in the design of transformers, but there are exceptional applications. As mentioned earlier, discharge lighting circuits require a supercharging transformer with “loose” (bad) voltage regulation to ensure reduced voltage after an arc is placed through the lamp. One way to meet this design criterion is to design the transformer with flux leakage paths so that the magnetic flux bypasses the secondary winding(s). The resulting leakage flow creates leckinduktivity, which in turn creates the poor regulation required for discharge lighting. Iron is a good conductor of electricity, but not as good as copper or aluminum from which wire windings are usually made.

Therefore, these “eddy currents” must overcome significant electrical resistance when circulating in the core. When they overcome the resistance of iron, they release force in the form of heat. Therefore, we have a source of inefficiency in the transformer that is difficult to eliminate. The autotransformer shown above performs a power rise function. A downward autotransformer would look like the following figure. In addition, winding conductor insulation is a problem when high voltages occur, as is often the case in elevating and step-down current distribution transformers. Not only must the windings be well insulated from the iron core, but each winding must also be sufficiently insulated from the other to maintain the electrical separation between the windings. Since transformers are essentially AC devices, we need to be aware of the phase relationships between the primary and secondary circuits. We can represent the waveforms of the primary and secondary circuits and see the phase relationships. Energy losses from transformers tend to worsen with increasing frequency. The skin effect in the winding conductors reduces the cross-section available for the electric charge flow, increasing the effective resistance as the frequency increases and more power is generated by the resistive power dissipation. Magnetic core losses are also exaggerated with higher frequencies, eddy currents, and hysteresis effects.

For this reason, large transformers are designed to operate efficiently in a limited frequency range. Given how we can tap into each transformer winding to get the equivalent of multiple windings (albeit with a loss of electrical insulation between them), it makes sense that it makes sense to completely dispense with galvanic insulation and build a transformer from a single winding. In fact, this is possible, and the resulting device is called autotransformer: special transformers, called peak transformers, take advantage of this principle to generate short voltage pulses near the ends of the source voltage waveform. The core is designed to saturate quickly and abruptly, at voltage levels well below the peak. This results in a significantly shortened sinusoidal flow waveform and secondary voltage pulses only when the flow changes (below saturation levels): on the other hand, if the points of each transformer winding do not match, the phase shift will be 180 ° between primary and secondary, as follows: the winding with more inductance has a higher voltage and less current than the other. Since both inductors are wrapped around the same base material in the transformer (for the most efficient magnetic coupling between the two), the parameters that affect the inductance for both coils are the same, except for the number of revolutions in each coil. If we look again at our inductance formula, we see that the inductance is proportional to the square of the number of coil turns: audible noise is an effect that is mainly due to the phenomenon of magnetostriction: the slight change in length that a ferromagnetic object shows during magnetization. The well-known “buzzing” of course in large power transformers is the sound of the iron core expanding and contracting at 120 Hz (twice the system`s frequency, which is 60 Hz in the United States) – a cycle of contraction and expansion of the core for each peak of the waveform of the magnetic flux – plus the noise generated by mechanical forces between the primary and secondary windings. Again, maintaining low levels of magnetic flux at its core is essential to minimize this effect, which is why ferroresonant transformers – which have to operate in saturation for much of the current waveform – operate both hot and noisy. .