Do you know what transformers are, what are they for and what are their characteristics? Electric transformers are extremely important and fundamental machines, with different applications. Knowing the importance of electrical transformers, Mundo da Elétrica explains in this article what a transformer is, its applications and characteristics. Come on guys!
Transformers: What are they?
Like motors and generators, transformers are also considered electrical machines, but they are electrical machines at rest and that work only on alternating current circuits. Transformers have the ability to transmit electrical energy from one circuit to the other through magnetic fields, transforming the voltage and current values at the same time.
Because of the action of this magnetic field, transformers have the ability to convert AC electrical energy with a certain frequency and voltage, into another AC electrical energy of the same frequency, but with a different voltage level, that is, it is capable of raising or decrease the output voltage in relation to its input.
There are several types of transformers, each of which has a specific construction, size and purpose. An important detail about transformers is that, theoretically, they have to transfer all the power applied in the primary to the secondary, so there is a change in both the voltage and the output current in relation to their input.
Transformers are widely used in electrical devices and installations, operating as a lift, lower or isolator transformer. The very common application for transformers is in the transport of large amounts of electrical energy over long distances, thus reducing voltage drops along the paths.
In this transport of electrical energy, after generation, the voltage levels are high for the energy to be transported by the transmission lines, in order to reduce the voltage drops. After traveling long distances, these voltage values are reduced and then distributed to consumers.
Another interesting application that we can mention for the transformers is in the converter circuits, because besides being useful to control the voltage levels they also act as insulators, for example, eliminating noise, among many other applications.
The basic model of a transformer, which is represented in the image below, consists of two or more coils of wire wrapped around a ferromagnetic core. Since these coils are usually not directly interconnected, so the only connection between these coils is the common magnetic flux present within the core. Due to this characteristic, the transformer is also used as an insulator in electrical circuits.
The transformers have an input and an output, the primary and the secondary winding respectively. In this way, we connect an AC power source to the primary winding of the transformer, while in the secondary winding of the transformer we connect the loads, as this is where energy will be supplied to them. It is important to note that in addition to the primary and secondary windings if there is a third winding, it will be termed as a tertiary winding.
When performing calculations and dimensioning of transformers, we use an ideal model, that is, we do not consider magnetic losses. This means that the magnetic permeability of the nucleus is considered infinite and the reluctance is zero, which facilitates the conduction of the magnetic flux. Below is the image that represents the relationships between voltage, current, and the number of turns of the primary and secondary of a transformer.
high performance and this is due to the lack of any moving parts in its interior, there is no friction energy as in motors and generators moreover there is no mechanical losses in the transformer. An important detail in relation to transformers is, the higher the power, the higher the transformer’s performance.
We can say that the losses of a transformer are electrical losses and magnetic losses, where:
- Electrical losses, also called copper losses, occur due to the ohmic resistance of the transformer windings;
- Magnetic losses also called copper losses, occur because of the alternating magnetic field and the currents induced in the iron core of the transformer.
There are several types of transformers such as current transformers. If you want to know more about this electric machine, below we have a video from the Mundo da Elétrica channel that explains what explains current transformers, their applicant, and characteristics.