Dry-type transformers are essential components for many indoor applications, from data centers to hospitals. These efficient units provide safe voltage transformation without the use of flammable liquid coolants.
Dry-type transformers rely on air or solid insulation materials such as epoxy resin and the like, making them a wonderful choice for indoor applications. Dry-type transformers are also known for their easier installation features, compact and lightweight design, and resistance to moisture, dust, and contaminants when properly enclosed.
Understanding the anatomy and nature of a dry-type transformer is critical to optimizing performance, ensuring safety, and planning for maintenance. In this article, we have explained the key components of a dry-type transformer.
Core
Core is the backbone of any transformer, including dry type transformers. It is usually made of laminated silicon steel sheets to minimize eddy current losses.
Dry-type transformer core is responsible for conducting magnetic flux between primary and secondary windings. Cores are designed either as “core-type”, which is wrapped around windings, or “shell-type”, which is windings wrapped around the core.
Windings
Windings are coiled conductors that help carry current and create the necessary electromagnetic induction. The primary winding of a dry-type transformer is connected to the input voltage source, while the secondary winding provides the transformed output voltage.
Windings are usually made of copper or aluminum and coated with enamel, epoxy, or resin to prevent short circuits.
Insulation Systems
Insulation is one of the most important parts for any type of transformer, including dry-type transformers, to prevent failures and ensure longevity.
Dry-type transformers usually have three types of insulation;
- Air: Provides natural cooling for smaller, low-voltage units.
- Vacuum Pressure Insulation (VPI): In this type of insulation, the windings are dipped in resin and cured under vacuum for moisture resistance.
- Cast Resin: Cast resin encapsulates windings in epoxy for superior protection against harsh environments and various damaging factors.
Cooling System
Cooling systems in dry-type transformers typically rely on air circulation or various advanced materials to dissipate heat.
Natural Air Cooling (AN) systems use vents and fins for passive cooling in low-power units for smaller applications. Forced Air Cooling (AF) adds fans to increase airflow for higher voltage loads.
High-temperature insulation with heat-resistant materials allows safe operation under thermal stress, especially for applications in industrial factories and the like.
Enclosure
Enclosure is the outer part of dry-type transformers that protects the internal components from environmental damage. It is usually made of steel, aluminum, or stainless steel with corrosion-resistant coatings.
The Ingress Protection (IP) rating of a dry-type transformer defines its resistance to dust and moisture. You can also choose a transformer with an explosion-proof or weatherproof enclosure for hazardous areas.
Bushing and Terminals
Bushings and terminals are the parts that connect your transformer to external circuits. Bushings are the insulated connectors that safely carry current through the enclosure. Terminals provide secure points for cable connections.
Tap Changers
Tap changers are used to adjust the transformer turns ratio to maintain the desired stable output voltage. Off-load tap changers require the transformer to be de-energized to adjust the taps, while on-load tap changers can be used during operation without interrupting voltage control.
Monitoring and Protection Devices
High-end, modern dry-type transformers typically include integrated safety and performance systems such as temperature sensors, humidity sensors, or surge arresters. These devices allow operators to track temperature fluctuations, moisture intrusion into the enclosure, and protect against voltage spikes from lightning or switching.
Accessories
Dry-type transformers may have other accessories and optional components such as wheels, silencers, or IoT-enabled sensors for remote monitoring and real-time diagnostics. You can customize your dry-type transformer to meet your needs.
Why Do Quality Components Matter in Dry-Type Transformers?
The reliability and performance of a dry-type transformer is directly related to the quality of its components. Substandard components or poor workmanship can result in premature insulation failure due to overheating, inefficient cores or windings, or safety hazards such as arcing and short circuits. It is also important to select a high quality dry type transformer for uninterrupted, reliable power transfer.
Esta Transformers’ expert engineers build our equipment with precision-engineered components, high-quality cores, the highest quality insulation, and rugged enclosures to ensure optimal performance in any condition or application. With decades of experience and cutting-edge technologies, we provide the best solutions for our customers.