Transformers are the silent workhorses of modern electrical systems. From power stations to factories and commercial buildings, they ensure voltage levels are safely adjusted for efficient transmission and distribution. Behind every reliable transformer lies a combination of key components that work together to maintain performance, safety, and efficiency.

In the UAE, where transformers operate in high temperatures and often under demanding load conditions, understanding each component’s role is crucial for effective maintenance and long equipment life. In this article, we’ll explore the main parts of a transformer — from the core and windings to cooling systems, bushings, tap changers, and insulating oil — and discuss how Star Freight Trading supports local industries with high-quality transformer parts and expert guidance.

Core and Windings: The Heart of a Transformer

The core and windings form the central part of any transformer. Together, they perform the essential function of transferring energy from one circuit to another through electromagnetic induction.

The Core

The transformer core is typically made of laminated sheets of high-grade silicon steel. These laminations are insulated from one another to minimize eddy current losses, which in turn improves efficiency. The core provides a controlled magnetic path for the flux generated by the current flowing in the windings.

The design of the core—its shape, material, and stacking method—directly influences a transformer’s performance. In the UAE, transformers often face high ambient temperatures, so manufacturers use materials that can withstand heat without excessive loss or expansion. Our Services

The Windings

Windings are coils of conductive wire (usually copper or aluminum) wound around the core. Transformers have two main windings:

  • Primary winding, connected to the input (supply) voltage.

  • Secondary winding, connected to the output (load) side.

The number of turns in each winding determines the voltage transformation ratio. For example, a step-down transformer will have more turns on the primary winding than on the secondary.

Copper windings are common due to their high conductivity and mechanical strength, though aluminum is sometimes used for cost savings and lighter weight. Proper insulation between windings prevents electrical faults and maintains dielectric strength.

Star Freight Trading supplies transformer cores and winding materials designed for the UAE’s tough environmental conditions, ensuring long-term performance and reduced maintenance requirements.

Cooling Systems and Their Importance

Every transformer generates heat during operation due to electrical losses in the core and windings. If this heat isn’t managed properly, it can degrade insulation, reduce efficiency, and shorten the transformer’s lifespan. That’s why an effective cooling system is vital.

Types of Cooling Systems

Transformers use different cooling methods depending on their size, rating, and installation environment. The most common include:

  • ONAN (Oil Natural Air Natural): The simplest method, where natural oil circulation transfers heat from the windings to the tank walls, and air cools the external surface.

  • ONAF (Oil Natural Air Forced): Similar to ONAN but includes fans to increase air movement, improving cooling efficiency.

  • OFAF (Oil Forced Air Forced): Pumps circulate oil and fans enhance air cooling—used in large power transformers.

  • ODAF/ODWF: Advanced forced-oil cooling systems with water or air heat exchangers for high-capacity units.

Why Cooling Matters in the UAE

High ambient temperatures in the UAE make cooling systems especially critical. Transformers often operate outdoors under direct sunlight, so any cooling inefficiency can quickly lead to overheating. Dust and sand can also clog air filters or fans, further reducing performance.

Routine maintenance of fans, radiators, and oil circulation pumps helps keep operating temperatures under control. Star Freight Trading provides replacement cooling components and accessories for all transformer types used in UAE industrial and utility networks.

Bushings, Insulators, and Protective Devices

While the core and windings manage electrical transformation inside the unit, bushings and insulators ensure that electricity enters and exits safely without short-circuiting or leakage.

Bushings

Bushings are insulating devices that allow electrical conductors to pass through the grounded transformer tank safely. They are typically made from porcelain or composite materials with high dielectric strength. In high-voltage transformers, condenser-type bushings are used to distribute the electric field evenly across insulation layers.

A cracked or contaminated bushing can lead to flashovers or oil leaks, making inspection and cleaning essential — especially in the UAE’s dusty, humid, and salt-laden coastal environments.

Insulators

Insulators support electrical conductors while preventing unwanted current flow. They’re used on transformer terminals, control panels, and switching equipment. Materials like epoxy resin, porcelain, or polymer composites are chosen based on voltage class and environmental exposure. Our Products

Protective Devices

Protective devices safeguard the transformer from internal faults, overloads, and external disturbances. Common ones include:

  • Pressure relief valves to release internal pressure buildup.

  • Buchholz relays to detect gas accumulation from insulation breakdown.

  • Temperature indicators for oil and winding monitoring.

  • Silica gel breathers to prevent moisture entry into the transformer oil.

Star Freight Trading offers a range of bushings, insulators, and protection accessories, ensuring that UAE-based operators maintain both safety and performance in their transformer systems.

Tap Changers and Voltage Regulation

No power grid operates with perfectly stable voltage. Loads vary, and so does demand. That’s where tap changers come in.

Function of Tap Changers

A tap changer adjusts the transformer’s turns ratio, allowing operators to regulate the output voltage under varying conditions. By changing the number of turns in the winding connected to the circuit, voltage can be increased or decreased slightly without interrupting supply.

Types of Tap Changers

  • Off-Load Tap Changer (OLTC): Adjustments can only be made when the transformer is de-energized. Common in distribution transformers.

  • On-Load Tap Changer (OLTC): Allows voltage adjustment while the transformer is in service. Essential for power transformers that must maintain steady output under fluctuating load conditions.

Importance in UAE Systems

With fluctuating grid loads and rising industrial demand, UAE utilities and industries rely on transformers with on-load tap changers for real-time voltage regulation. Regular servicing of these mechanisms — checking contacts, oil levels, and switching motors — is vital to prevent operational failure.

Star Freight Trading supplies and supports both off-load and on-load tap changer systems, providing genuine replacement parts and technical assistance for UAE customers.

Transformer Oil and Its Role in Insulation and Cooling

Transformer oil plays two vital roles: it insulates the internal components and helps dissipate heat. It fills the tank, surrounding the core and windings, acting as both an electrical insulator and a coolant.

Functions of Transformer Oil

  1. Electrical Insulation: The oil provides dielectric strength between energized parts, reducing the risk of arcing or short circuits.

  2. Heat Dissipation: It absorbs heat from the core and windings and transfers it to the tank walls for cooling.

  3. Protection from Moisture and Oxidation: The oil prevents moisture ingress and oxidation of metal components.

Types of Transformer Oil

  • Mineral Oil: The most common, known for good dielectric strength and thermal stability.

  • Silicone Oil: Used where fire resistance is important.

  • Natural Ester Oil: A biodegradable and environmentally friendly option with high moisture tolerance.

Oil Quality Monitoring

Regular oil testing is critical for ensuring reliability. Key parameters include dielectric strength, moisture content, acidity, and dissolved gas levels. Over time, oil degrades due to heat and contamination, reducing its insulating and cooling effectiveness.

In the UAE, where temperature extremes accelerate oil aging, timely testing and replacement are essential. Star Freight Trading provides high-grade transformer oils and can assist clients with oil analysis services to keep equipment running efficiently.

Routine Inspection and Component Maintenance

Routine inspection is the foundation of transformer reliability. In the UAE’s harsh climate, where sand, dust, and heat can all impact performance, a structured maintenance program is essential.

Inspection Checklist

  1. Visual Inspection: Check for oil leaks, damaged bushings, corroded terminals, or rust on the tank.

  2. Oil Level and Quality: Ensure oil level is adequate and that it remains clear and free of sludge.

  3. Cooling Equipment: Inspect fans, radiators, and pumps for proper function. Clean any dust buildup.

  4. Protective Devices: Test Buchholz relays, pressure valves, and alarms regularly.

  5. Temperature Monitoring: Record oil and winding temperatures to detect overload or cooling issues.

  6. Tap Changer Operation: For on-load systems, check contact wear and oil contamination inside the diverter chamber.

Preventive Maintenance Practices

  • Keep transformers sheltered where possible to reduce exposure to heat and dust.

  • Schedule oil sampling and Dissolved Gas Analysis (DGA) every six months for high-value units.

  • Maintain proper grounding and inspect cable terminations.

  • Replace worn gaskets and seals promptly to prevent moisture ingress.

Routine attention to these details can prevent costly downtime and extend transformer life by many years.

Star Freight Trading supports UAE clients with preventive maintenance materials, replacement components, and consultation services. Their technical team helps operators design maintenance schedules suited to local operating conditions.

Transformers are complex, precision-engineered systems where each component — from the core and windings to the cooling oil — plays an essential role in reliability and efficiency. Understanding these parts and maintaining them properly is the key to long service life, especially under the UAE’s demanding climate.

By focusing on quality materials, correct installation, and regular maintenance, operators can avoid failures and achieve consistent performance across power and industrial systems.

For dependable components, oils, and replacement parts, Star Freight Trading provides UAE industries with trusted transformer solutions backed by technical expertise. Whether you need new cores, bushings, cooling equipment, or insulation materials, Star Freight ensures your transformers keep running smoothly, safely, and efficiently.

Frequently Ask Questions

1. What are the main components of a transformer?

The main components include the core, windings, cooling system, bushings, tap changers, and transformer oil. Each part plays a critical role in electrical performance and insulation.

2. Why is transformer cooling important in the UAE?

Due to high ambient temperatures, transformers in the UAE are prone to overheating. Efficient cooling systems and regular maintenance help prevent failures and extend lifespan.

3. What is the purpose of transformer oil?

Transformer oil insulates internal components and removes heat from the core and windings. It also prevents oxidation and moisture buildup that could damage insulation.

4. How often should transformer components be inspected?

Visual inspections should be performed monthly, with full preventive maintenance and oil testing at least once a year. In harsh UAE conditions, semi-annual checks are recommended.

5. What are tap changers used for in transformers?

Tap changers adjust the voltage ratio of the transformer to regulate output voltage. On-load types can make adjustments while the transformer is energized.

6. Where can I find reliable transformer parts in the UAE?

Star Freight Trading supplies premium transformer components, oils, and accessories across the UAE, offering expert advice and maintenance support for all transformer types.