Different Types of Transformers and Their Applications – Ultimate Guide

Different Types of Transformers and Their Applications – Ultimate Guide

Today’s civilization would be completely different if we didn’t have transformers. They play a crucial role in electrical systems, helping to transfer electrical energy between different circuits. Each type of transformer serves a unique purpose and is specifically designed to meet the electrical requirements of the application which we will explore in this comprehensive guide.

What is a transformer?

Before diving into the different types of transformers, let’s first understand the basic concept of a transformer. A transformer is an electrical device that consists of two or more coils of conducting wire, known as primary and secondary windings. These windings are wound around a core, which is typically made of iron or other magnetic materials.

When an alternating current (AC) flows through the primary winding of a transformer, it creates a changing magnetic field around the core. This changing magnetic field induces a voltage in the secondary winding, resulting in the transfer of electrical energy from the primary to the secondary side of the transformer.

An electrical transformer is an essential and widely employed electrical machine used in power systems. Electrical transformers can be categorized into various types depending on different factors. We will go over the most commonly used classifications in the next sections.

Types of transformers based on their application

Power transformers

Power transformers primarily serve the transmission networks that operate at higher voltage levels, with ratings such as 400kV, 200kV, 110kV, 66kV, and 33kV. Many of these power transformers have substantial ratings exceeding 200MVA. They are typically installed in generating stations and transmission substations that require high-capacity transformers. Power transformers are designed for maximum efficiency, reaching 100%, and they are larger in size compared to distribution transformers.

Due to the impracticality of directly distributing power to consumers at very high voltages, step-down power transformers are employed to reduce the voltage to the desired level. These transformers may not operate at full load continuously, resulting in core losses throughout the day, while copper losses depend on the load cycle of the distribution network.

When power transformers are connected to the transmission network, load fluctuations are generally minimal since they are not directly linked to end consumers. However, if they are connected to the distribution network, load fluctuations become more apparent.

Power transformers at transmission stations are continuously loaded for 24 hours, leading to both core and copper losses throughout the day. Power transformers are cost-effective when power is generated at lower voltage levels. If voltage levels are increased, the current in the power transformer decreases, causing I2R losses and increased voltage regulation.

At TTES, you can select from a variety of power transformers, such as dry-typeone-phase pad, and three-phase pad transformers that are swiftly shipped to you at unrivaled delivery times averaging just 20 weeks across the whole USA. If you’re interested, get in touch with us and request a free quote!

Distribution transformers

Distribution transformers (often referred to as consumption transformers) serve as the final phase in the power distribution system. These transformers are step-down devices, responsible for converting high grid voltages into the lower voltages required by end customers, typically 110V or 230V. They can exist in both single-phase and three-phase configurations.

Distribution transformers vary in size, ranging from smaller to larger units, depending on their capacity or rating. They can also be classified based on the type of insulation they use, such as dry-type or liquid-immersed. These transformers are typically constructed using laminated steel plates, often in a C-shaped core configuration.

Furthermore, the classification of distribution transformers can be based on their installation location. They may be mounted on utility poles, known as pole-mounted distribution transformers, placed within underground chambers, mounted on concrete pads (referred to as pad-mounted distribution transformers), or enclosed within steel boxes.

Instrument transformers

Instrument transformers are electrical devices utilized for the conversion of current and voltage levels. Their primary purpose is to ensure safe isolation of the secondary winding when the primary winding is exposed to high voltage and high current inputs. This protective measure prevents potential damage to measuring instruments, energy meters, or relays connected to the secondary side of the transformer. Instrument transformers can be categorized into two main types:

Current transformers

Current transformers (commonly abbreviated as CT) serve a dual purpose in the realm of electricity – measurement and protection. They come into play when the current is too high to be directly applied to measuring instruments, effectively transforming the high current into a suitable value for the circuit.

In these transformers, the primary winding is linked in series with the primary power supply. It works in conjunction with various measuring devices such as ammeters, voltmeters, wattmeters, or protective relay coils, facilitating the measurement and control of electricity. These transformers are engineered to maintain precise current ratios and phase relationships, ensuring accurate readings on the secondary side. The concept of ratio holds significant importance in the context of current transformers.

Potential transformers

A potential transformer (type of instrument transformer often abbreviated as PT) is a specialized instrument transformer designed to convert high primary voltage levels into lower secondary voltage values. This transformation serves to reduce the voltage to a safe and manageable level that standard low-voltage instruments, such as wattmeters, voltmeters, and watt-hour meters, can accurately measure.

Potential transformers play a crucial role in ensuring that high-voltage electrical systems can be safely and accurately monitored and controlled using conventional measuring instruments. These transformers are essential components in various applications, from industrial power systems to utility grids, where voltage measurement and control are vital for operational efficiency and safety.

Zigzag transformers

Zigzag transformers are specialized electrical transformers known for their unique winding arrangement. Their winding pattern resembles a zigzag, allowing them to provide an effective neutral connection in electrical systems, especially ungrounded ones. Zigzag transformers are also valuable for mitigating harmonics and controlling voltage imbalances in power systems. While not as common as other transformer types, they play a crucial role in ensuring the stability and safety of electrical grids, making them essential components in specific applications where grounding and harmonic management are vital

Types of transformers based on the insulation

Dry-type transformers

Dry-type transformers are a transformer variety that does not rely on insulating liquids, unlike transformers in which windings or cores are submerged in such liquids. Instead, these transformers house their windings and cores in a sealed tank pressurized with air. Despite the absence of liquid insulation, they maintain a high level of safety.

Dry-type transformers can be further categorized into two main types: Cast Resin Dry Type Transformers (CRT) and Vacuum Pressure Impregnated Transformers (VPI).

Liquid-filled transformers

A liquid-filled transformer is a voltage transformation apparatus that employs a liquid-cooling mechanism to regulate the transformer’s temperature. In contrast to dry-type transformers, the core, and windings of a liquid-filled transformer are encased within a welded steel tank that is filled with insulating liquid. During operation, the heat generated by the coil and iron core is initially transferred to the insulation liquid and subsequently dissipated into the cooling medium. Additionally, based on their capacity, these transformers can be categorized as immersed natural cooling transformers or immersed forced air cooling transformers.

Types of transformers based on the number of phases

Single-phase type transformers

A single-phase transformer is a type of transformer that operates with a single-phase alternating current. It consists of primary and secondary windings and is commonly used in residential and small commercial applications.

Single-phase transformers are used to transfer electrical energy in smaller power supplies, such as household appliances and lighting systems.

Three phase type transformers

In contrast, a three-phase transformer operates with a three-phase alternating current. It consists of three primary windings and three secondary windings, arranged in either a delta or wye configuration.

Three phase transformers are commonly used in power distribution systems, industrial machinery, and large-scale commercial applications due to their ability to handle higher power loads.

Types of transformers based on voltage conversion

Step up transformer

A step-up transformer increases the voltage from the primary winding to the secondary winding. This transformer type is commonly used in power transmission systems to raise the voltage to a higher level, minimizing power loss during long-distance transmission.

In the realm of electronics, step-up transformers find common use in devices like stabilizers and inverters where the objective is to convert a lower voltage into a significantly higher voltage.

Additionally, step-up transformers play a vital role in electrical power distribution. Applications related to power distribution necessitate the use of high voltage. Therefore, step-up transformers are often deployed in the grid to elevate the voltage level before distribution takes place.

Step down transformer

On the other hand, a step-down transformer is a transformer type that reduces the voltage from the primary winding to the secondary winding. It is commonly used in power distribution systems to convert high-voltage electricity from power plants to lower voltage levels suitable for household and industrial use.

In the realm of electronics, many devices operate on various low voltage levels such as 5V, 6V, 9V, 12V, 24V, or sometimes 48V. Step-down transformers are essential to convert the standard single-phase power outlet voltage of 230V AC to these lower voltage levels. They play a crucial role in instrumentation and are a fundamental component in the power section of various electrical equipment. Step-down transformers are also integral to power adapters and the circuits of mobile phone chargers.

In the electrical domain, step-down transformers are usually employed within electrical distribution systems that function at very high voltages, ensuring efficient and cost-effective power transmission over long distances. Their purpose here is to convert high voltage into a lower voltage supply line, making step-down transformers indispensable for these power delivery requirements.

Isolation transformer

An isolation transformer maintains consistent voltage levels between its primary and secondary windings, as the winding ratio remains 1:1. This means the number of turns in both the primary and secondary windings is the same, resulting in equal voltages.

The primary function of an isolation transformer is to create electrical separation between the primary and secondary sides. There are no direct electrical connections between these two sides; instead, conduction occurs solely through magnetic flux. This configuration serves safety purposes and prevents the transmission of electrical noise from the primary side to the secondary side, and vice versa.

Types of transformers based on core material

Air core transformers

In this type of transformer, both the primary and secondary windings are positioned without the presence of a magnetic core. Instead, they rely on air as the medium. This results in a relatively low level of mutual inductance within the air-core transformer, meaning that there is a higher reluctance to the generated flux due to the air medium.

Smaller electronic devices often utilize air-core transformers, which are essentially constructed like antenna coils. They find widespread use in communication devices, particularly in portable applications. These transformers, lacking a solid core, are well-suited for portable and compact devices and are commonly found in radio transmission systems.

Ferrite core transformers

This transformer variety employs a magnetic core composed of ferrite, serving as the foundation for the construction of power transformer windings and other components. Ferrite cores are known for their high magnetic permeability, making them particularly suitable for high-frequency applications like switch-mode power supplies.

The key advantage of ferrite cores lies in their ability to minimize losses at higher frequencies, which is why they find widespread usage in the cores of radio frequency (often abbreviated as RF) transformers. Furthermore, ferrite core transformers come in various sizes and shapes, allowing for customization to meet specific application requirements.

Iron core transformers

In this design, both the primary and secondary windings are wrapped around multiple soft iron plates, creating an efficient pathway for the magnetic flux. Unlike air-core transformers, this type offers significantly less reluctance to the flux linkage due to the iron’s conductive and magnetic properties.

These transformers are highly capable of magnetic permeability, making them valuable in applications where controlling and directing magnetic fields is crucial, such as in electric motors, generators, and inductors. Various types of core plates are available in the market, offering flexibility in terms of core size and shape. These transformers are widely utilized, but it’s important to note that they tend to be heavy and bulky due to the iron core.

Toroidal core transformers

The toroidal core transformer utilizes a distinctive ring-shaped magnetic core, resembling a donut or circular ring. These transformers are passive electronic components, featuring a circular, ferromagnetic core around which wire is wound.

Thanks to their inherent design, toroidal transformers exhibit minimal leakage inductance and offer exceptionally high inductance levels. They find extensive application in a variety of electronic circuits, including power supplies, inverters, and amplifiers.

Conclusion and TTES

In conclusion, transformers are essential components in electrical systems, enabling the efficient transfer of electrical energy between different circuits. By understanding the different types of transformers and their specific uses, you can make informed decisions when it comes to selecting the right transformer for your applications.

At TTES, you have the option to choose from dry-typeone-phase pad, and three-phase pad transformers. These quality transformers are quickly customized and manufactured with average shipping times of just 20 weeks throughout the entire USA. The delivery timeframe is primarily influenced by the quantity of transformers you order. Additionally, we offer comprehensive installation manuals and drawings to ensure a smooth process. Feel free to reach out to us and request a free quote. We are here to provide guidance and help you get a customized power transformer!

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