What Is a Transformer, and Where Is It Used?

9 May 2023

A transformer, also known as a “trafo,” is a device responsible for altering the characteristics of electrical energy to the desired values.

The term “trafo” is derived from the English word “transformer,” and its Turkish equivalent is “dönüştürücü,” meaning “converter.” As the name implies, transformers are used for the conversion of electrical energy.

In short, transformers provide electromagnetic induction to the existing electrical current between two or more circuits.

What Is the Purpose of a Transformer?

The primary purposes of transformers involve achieving energy transfer between two or more circuits through electromagnetic induction. To enable the transmission of electrical energy over long distances, transformers increase the voltage. Voltage is raised while keeping the current at a level where it does not cause any harm.

This allows the electrical current to be transmitted at the desired intensity and dimensions.

Therefore, transformers are utilized to adjust the level of current or voltage within an electrical circuit.

Transformers designed for energy distribution and transmission come in various types to meet specific needs and applications.

What Are the Types of Transformers?

Transformer types vary depending on their intended applications. Generally used transformer types include:

• Isolation Transformers
• Current Transformers
• Power Transformers
• Distribution Transformers
• Dry-Type Transformers
• Oil-Immersed Transformers
• Voltage Transformers

These transformers have different characteristics depending on their intended applications. When examining the features of transformer types:

Dry-Type and Oil-Immersed Transformers:

Oil-immersed transformers dissipate heat generated inside the transformer to the external environment. This heat dissipation is achieved through oil within the winding.

Especially when dealing with high power levels, they help prevent overheating issues. Oil-immersed transformers are manufactured in two main types: sealed tank and conservator tank. The choice between these types depends on the application area.

The structure of oil-immersed transformers includes:

• Core (also known as the nucleus)
• Tank and cover
• Windings
• Bushings
• Terminals
• Cable boxes
• Voltage regulator
• Expansion tank
• Other accessories

Air-cooled transformers are typically used in both outdoor and indoor settings. They are commonly found in industrial areas, construction sites, and factories.

Oil-immersed transformers are manufactured with power capacities ranging from 50 to 20,000 KV and system voltages of up to 36 KV.

Dry-type transformers dissipate the heat generated inside the transformer through air cooling. Their key feature is the absence of explosion hazards, making them suitable for crowded environments where people gather.

Dry-type transformers are used in various applications, including schools, hospitals, and shopping centers.

The main difference between oil-immersed and dry-type transformers is the absence of explosion hazards in dry-type transformers. This is why dry-type transformers are preferred in areas with large populations.

Current Transformers (CTs):

Current transformers are typically used in energy consumption measurements and circuit protection systems. They have a feature known as the transformation ratio, which is used to measure the current between circuits. Current transformers multiply the transformation ratio by the current they read and provide the current value for the circuit.

Power Transformers:

Power transformers are used to maintain voltage frequency stability by altering voltage values. They are made up of thin silicon steel sheets and windings wrapped around the core with insulated conductors.

Power transformers are selected based on different voltage classes. They come in various types, including:

• Low-voltage transformers
• Medium-voltage transformers
• High-voltage transformers
• Extra-high-voltage transformers

Distribution Transformers:

Distribution transformers are used to lower the voltage of electrical energy for distribution purposes. They are produced as oil-immersed, hermetically sealed, or dry-type transformers. The choice depends on the specific application and purpose.

Voltage Transformers:

Voltage transformers transfer primary circuit voltage to a secondary circuit, allowing for voltage measurement. They reduce the primary voltage to a desired level through magnetic coupling and transfer it to the secondary side.

Isolation Transformers:

Isolation transformers are used to establish electrical connections in a circuit without the need for conductors. In the event of a fault in the transformer, the other side of the circuit is isolated.

The Operating Principle of a Transformer

The operating principle of a transformer involves the transmission of electric current from one conductor to another through the intermediary of a magnetic flux.

When alternating current is applied to the transformer, it flows through the primary winding and generates a magnetic field in the core. This magnetic field induces a voltage in the secondary winding by cutting across it. In other words, the voltage applied to the primary is transferred to the secondary, either at the same voltage level, a lower voltage level, or a higher voltage level.

If you found our article titled “What Is a Transformer, and Where Is It Used?” satisfactory, you may also want to take a look at our article titled “Types of Transformers.”