What is a Transformer? What is it for and what types are there?

A transformer, also known as a transformer, is an electrical machine that transfers electrical energy between two circuits by transforming voltage and current levels without changing the frequency, through electromagnetic induction. It consists of primary and secondary windings wound on a single metal core and does not involve any mechanical movement under normal conditions. So, the shortest answer to the question of what a transformer is and what it does is; It is a transformer that safely converts the alternating voltage in a circuit to another voltage level and transfers electrical energy from one circuit to another via a magnetic field.

The transformer operating principle, that is, the transformer operating principle, is based on Faraday's law of electromagnetic induction. Alternating voltage applied to the primary winding creates a variable magnetic flux on the core. When this flux cuts the secondary winding on the same core, a voltage proportional to the number of windings is induced. Thus, energy transfer is provided between the primary circuit and the secondary circuit without metallic contact. The basic relationship known as the transformer formula; The voltage ratio is approximately equal to the winding number ratio: V2/V1 ≈ N2/N1. The relation I2/I1 ≈ N1/N2 is used for currents. In an ideal transformer, the input and output apparent power are approximately equal (S1 ≈ S2 ≈ V × I); These expressions are used in transformer power formula and conversion ratio calculations.

The answer to the question of which current the transformer works with is clear: Classic power transformers and transformers are designed to work only with alternating current (AC). Applying direct current (DC) to the primary winding causes the core to become magnetized and enter saturation, resulting in excessive current draw with very high magnetic flux; This may cause overheating of the transformer, deterioration of winding insulation and serious malfunctions. So "is the transformer AC or DC?" The answer to the question is almost always AC in practice.

The answer to the question why transformer is used is; to reduce losses, adjust the voltage level and transport electrical energy safely. If we think about what to do with a transformer; When the voltage is increased and the current is decreased in transmission lines, I²R losses decrease and conductor cross-sections become smaller. In the distribution and facility, the voltage is reduced again and brought to levels where devices and people can operate safely. What happens if there is no transformer? We could neither transport electrical energy efficiently between cities many kilometers away, nor reduce it to safe voltage levels such as 230/400 V in homes and workplaces. In other words, the backbone of the modern electrical grid is transformers and transformers.

In energy systems, power transformers that increase the voltage in production plants, intermediate transformers that change the voltage level along transmission lines, and distribution transformers that reduce the voltage level in residential areas are generally used. Large industrial facilities have transformers and MV cubicles that convert from MV to LV in their own substations. These centers are used for field testing, maintenance and repair work. Bursa HV/MV testing, maintenance and repair with transformer maintenance and testing services can be planned together.

Basic components of a transformer; magnetic core, primary winding, secondary winding, insulation materials, tank or body and cooling mechanisms that protect the windings and core. While transformer oil is used for insulation and cooling in oil-filled transformers, epoxy resin or air cooling is preferred in dry type transformers. This structure, shown schematically with the transformer symbol in electrical projects, is actually a very complex machine with insulation, cooling and mechanical protection details.

Transformer types according to the purpose of use; Power and distribution transformers used in energy transmission and distribution can be summarized as isolation transformers and measurement transformers (current transformer and voltage transformer) that provide galvanic isolation between the network and the load. Measurement transformers convert high voltage and current levels into safe values ​​that measuring instruments can read; Choosing the correct transformer equivalent circuit and ratios is important for the healthy operation of protection relays and measurement systems.

Transformers according to their structure and cooling method; They are divided into two main groups: oil-filled transformers and dry type transformers. Oil-filled transformers are cooled by natural or fan circulation of transformer oil (e.g. cooling codes such as ONAN, ONAF). Dry type transformers are generally preferred in indoor applications with low fire risk and low maintenance needs. Therefore, "dry type transformer or oiled transformer?" The answer to the question is often given according to the working environment and fire safety requirements.

Transformers are classified as single-phase and three-phase according to the number of phases. Since three-phase systems are widely used in the network, the transformers in the energy transmission and distribution line are mostly three-phase transformers. However, in some special applications or small powers, single-phase transformers are also used. The transformer winding number formula is used to calculate the number of winding turns according to the desired input-output voltages in these single-phase or three-phase transformers.

When choosing a transformer; power (kVA), primary and secondary voltage levels, working environment (indoor/outdoor), cooling method, short circuit resistance, connection vector group and operating conditions must be taken into consideration. An incorrectly selected transformer causes both efficiency loss and premature failure. In new substation installation or power increase projects, this selection and calculation process LV/MV/HV project design and consultancy We manage it together with our services.

Transformer maintenance during operation; It includes steps such as taking oil samples in oil-based transformers and performing laboratory analyzes (e.g. DGA - gas analysis), periodically applying winding resistance, TTR (turning ratio), insulation resistance and power factor tests, performing hot spot scans with a thermal camera and checking connections. For such detailed maintenance and testing Bursa transformer maintenance, testing and oil analysis You can benefit from the services outlined on our page.

Regular tests and maintenance work extends transformer life, reduces unexpected failures and increases operating continuity. Periodic transformer maintenance is of critical importance, especially in industrial facilities, as a transformer failure means production loss and security risk. In order to carry out business and regulatory monitoring from a single source, you can transformer operation responsibility and general if necessary SA operation responsibility You can work integrated with our services.

We answered the questions of what a transformer is, how it works and what types there are, in a general framework on this page. For detailed engineering solutions, transformer testing and maintenance services and transformer oil analysis Bursa transformer servicesfor the business and regulatory side transformer operation responsibility and for your HV/MV equipment HV/MV testing, maintenance and repair You can review our pages and contact the Pow-Sys Power Systems team.