An Overview of Encapsulated Transformers: Applications and Advantages

March 15, 2024

Transformers are a fundamental component in our electrical networks, responsible for modifying voltage levels to meet various needs. Among the diverse types of transformers, encapsulated transformers hold a unique place due to their design and applications. In this article, we will explore what encapsulated transformers are, how they differ from other types, and where they are typically used.

Encapsulated Three Phase Dry Type Transformer Core
Encapsulated Dry Type Transformers

Understanding Encapsulated Transformers

Encapsulated transformers, also known as sealed or potted transformers, are designed to withstand harsh environments and ensure longevity and reliability. The term “encapsulated” refers to the process of sealing the transformer’s core and windings in a resin or epoxy. This sealant provides a barrier against moisture, dust, and other contaminants that could otherwise impair the transformer’s performance.

The encapsulation process involves placing the completed transformer in a mold, which is then filled with a resin material. Once set, this resin forms a solid, insulating barrier around the internal components. This barrier not only protects against environmental factors but also helps to improve heat dissipation, reduce noise, and prevent corrosion.

Applications of Encapsulated Transformers

Encapsulated transformers are used in a variety of settings, particularly where durability and protection against environmental conditions are required. Some common applications include:

ETAC encapsulated red dry type transformers lined up on the production floor
ETAC Encapsulated Dry Type Transformers
  1. Outdoor Installations: These transformers are ideal for outdoor use where equipment is exposed to the elements, such as moisture, particulates like dirt and debris. Their sealed nature protects them from rain, humidity, and contaminants.
  2. Marine Environments: Boats and offshore platforms benefit from encapsulated transformers due to their resistance to saltwater and moisture, significantly reducing the risk of corrosion and electrical faults.
  3. Industrial Settings: Factories and industrial plants often use encapsulated transformers due to their ability to withstand dust, dirt, and chemicals.
  4. Underground Systems: For underground electrical systems, such as those used in mining or tunnel lighting, encapsulated transformers provide necessary protection against dampness and soil contaminants.
  5. Food and Beverage Industry: In environments where cleanliness and hygiene are paramount, encapsulated transformers are used because their sealed design prevents the accumulation of bacteria and facilitates easy cleaning.
  6. Medical Facilities: In hospitals and clinics, these transformers can be found in medical equipment where safety and reliability are critical, and protection from contaminants is essential.

Advantages of Encapsulated Transformers

Encapsulated transformers offer several advantages over their non-encapsulated counterparts:

  • Environmental Protection: The resin encapsulation shields the transformer from moisture, dust, and other environmental factors that could lead to corrosion or electrical failures.
  • Safety: The encapsulation material is typically flame-retardant, reducing the risk of fire. Additionally, the sealed design prevents accidental contact with live components.
  • Durability and Longevity: By protecting the internal components from external elements, encapsulated transformers tend to have a longer operational life.
  • Noise Reduction: The resin helps to muffle the humming noise commonly associated with transformers, making them suitable for noise-sensitive environments.


Encapsulated transformers are a versatile and reliable solution for ensuring stable power in environments where traditional transformers would be vulnerable to damage. Their design makes them suitable for a wide range of applications and are primarily found in harsh environmental settings where the transformer could be exposed if not protected. By understanding where and why encapsulated transformers are used, electrical professionals and consumers can make informed decisions about their power supply needs, ensuring efficiency, safety, and longevity of the transformer.