Isolating transformer! What is it and what is it for?

Do you know what isolating transformers are, do you know their operating principle and what are they for? Do you know the applications of an insulating transformer, inside the electrical? How important are these devices on the premises? If you do not know any of these questions, or if there is any doubt on the subject, let us together learn a little more about this important topic, the isolation transformers without mysteries.

Features of transformers

Transformers are widely used electrical devices, their application extends to electronic devices, various machines, industrial applications from different segments and among other technological applications.

Isolating transformer for lowering voltage control

Virtually everything we have working in the world operates due to the use of some type of energy transformation, that is, transformers.

We are in an advanced technological phase, where the electro-electronic integration becomes increasingly complex and integrated with electrical devices such as transformers. Today it has become essential to understand fundamental concepts such as the operation of traffic and its applications. To understand the functioning of a device it is practically a prerequisite to understanding the operation of transformers, only then can a good technician understand the entire system of complex machines and equipment.

As the name tells us, transformers transform the electrical input voltage into another electrical output voltage, of a different intensity than the input. To carry out this transformation, the transformer uses magnetism to generate an induced voltage at the output of the transformer.

The transformers called isolators, receive this name because the electric voltage input is electrically isolated from the output, therefore, there is no electrical contact between the transformer output and input.

Operation of the isolating transformer

A transformer consists of two coils electrically isolated from each other but coupled in a magnetic core usually formed by silicon plates, this material has high magnetic permeability-increasing the magnetic efficiency of the system.

The coil that receives the input of the electric voltage is called the primary of the transformer because it receives primary voltage from the mains input. The second coil receives the name of secondary or transformer output, it is in this output that we find the magnetically induced voltage, this occurs by the flow of the magnetic field generated by the primary coil.

Diagram of the working principle of an ideal transformer

Basically the isolating transformers transfer energy or electrical power from one circuit to another, through the induction of the magnetic field generated by the primary coil and normally the values ​​vary in current and voltage, or act by modifying the electrical impedance values.

Operation occurs according to Faraday’s law, by electromagnetic induction. There are two winding coils of wires, which are called the primary circuit and secondary circuit as seen above. While in the primary an alternating current circulates that generate an electromagnetic field of varying flux, in the secondary current is produced in the same way, proportional to the electric current that flows in the primary, this relationship is called the transformation ratio of a transformer.

Isolating transformers depend on the variation of the magnetic flux, so they only work in alternating currents. Typically, these transformers are used to raise or reduce the voltage, or simply as galvanic isolation (electrical isolation) between parts of the same circuit.

Important relationships for Ideal model transformer

For an ideal model transformer we consider the following related mathematical truths:

Transformation ratio for dimensioning and electrical calculations of transformers

For the calculations and dimensioning of the isolating transformers to be carried out, we use an ideal model, for this model we consider the magnetic permeability of the core, which is the facility to conduct the magnetic flux as being infinite, that is, we do not consider magnetic losses, we determine that the reluctance to magnetic flux is zero. In this case, we also consider zero losses and no dispersion of the magnetic flux.

To fix the knowledge covered so far, we will apply the transformation relationships presented through a practical exercise, for this we have a single-phase step-down isolating transformer, with a 10/1 transformation ratio, where there are 200 turns in the primary (N1) and 20 turns on the secondary (N2) we know that the output current (I2) of the transformer is 10A, and the input voltage (V1) is 127V. With the data presented, what is the output voltage on the secondary (V2) and the current on the primary (I1)?

Resolution of the proposed exercise for dimensioning the output voltage and input current

Transformer types and applications

Isolating transformers can be classified in several ways, and can be classified according to the purpose, type, material of the core and the number of phases. Observe the classification of transformers by type and their main applications:

Current transformer:

The current transformer better known as TC, has the objective of measuring the electric current that travels through an electric cable. The magnetic field emitted by a conductor traversed by an electric current, induces a proportional electric current in a secondary winding, which in turn transmits this current to a lesser extent to measuring instruments.

The main application of current transformers is in control and automation of power circuits, especially when it comes to protection, as it allows the original current to be transformed into a smaller current and can thus be monitored by electronic control devices.

Potential transformers:

The potential transformers better known as TP´s are devices very similar to the current transformers, however their function is to lower the original circuit voltage so that its monitoring and measurement is safe.

Its principle of operation is the same already presented, the original voltage of the circuit generates a magnetic field that in turn produces an induced voltage in the secondary bearing, this voltage is proportional to the voltage that originated it, therefore, we can perform the monitoring and control of the circuit through electronic devices, its main application is in control and automation of power circuits.

Classification of transformers by type and according to their applications

Distribution transformer:

Distribution transformers are mainly used by energy distribution concessionaires and in power generation plants. These transformers are responsible for raising the voltage of the energy generators so that it can be transported to consumers, minimizing electrical losses.

Power Transformers:

They are used for generation and distribution of energy by concessionaires and plants, and electricity distribution substations, and substations of large industries, including special applications such as induction and arc furnaces, and rectifiers, they are used to perform lifting and high power scale voltage lowering.

Below we present a video that addresses concepts of isolation transformers, in addition to specifically presenting the transformation relationship of this equipment. Be sure to check out this excellent video:

When we approach transformers, we deal with a very important issue within the electrical sector, generally all devices, circuits and other applications use this important device to make their operation feasible, so the subject deserves to be explored and constantly updated. In this article we cover the main concepts of isolating transformers, also the types of transformers and their main applications, so we can have an overview of the vast field that addresses isolating transformers and transformers. Be sure to keep up to date on the subject as there is still much more to learn.