Three-Phase Transformers for Power Distribution & Industrial Applications
DOREXS three-phase transformers offer reliable performance, robust design, and customizable solutions tailored to industrial power distribution, motor drives, renewable energy systems, and heavy-duty electrical equipment. Get Customized Solutions
A three phase transformer is an electronic device used to convert three-phase alternating current voltage in a three-phase power system. It usually consists of three windings, corresponding to phase A, phase B and phase C of the three-phase power supply.
Three-phase transformers are widely used in power transmission and distribution, industrial equipment and large-scale infrastructure due to their efficient power transmission, stable power output, compact structure and multiple connection methods.
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Three-Phase Dry-type Transformers
Made of high-quality materials and advanced process technology. 160VA to 600KVA. This series of three-phase dry-type transformers replaces similar products of Siemens. Among them, the three-phase dry-type transformers between 160VA-16KVA have standardized appearance and installation dimensions, which are common to Siemens 4AP series. The products comply with international standards such as VDE0550, IEC439, and JB5555. This series of transformers does not require oil cooling, is environmentally friendly, safe, and easy to maintain. It is widely used in commercial buildings, data centers, hospitals, and subways.
Three-phase Autotransformer
The three-phase autotransformer is made of high-quality silicon steel sheets and excellent technology, with low no-load loss, no noise, low temperature rise and high efficiency. It is suitable for power distribution systems with a frequency of 50~60Hz and a voltage level of 380V/220V. The capacity is 1~800KVA and can be equipped with a chassis and temperature control protection system. DOREXS can design according to the customer's own requirements and tailor it according to the different needs of the customer. We will provide professional price quotes according to customer needs.
Three-phase Oil-Filled Transformer
10kV three-phase oil-immersed distribution transformer adopts high-quality cold-rolled grain-oriented silicon steel sheets, combined with advanced technology, effectively reducing no-load loss, load loss and noise. Unique coil design improves short-circuit resistance and reduces temperature rise. The corrugated oil tank has been strictly tested for leaks to ensure zero oil leakage risk. Equipped with a new strip-type tap changer, it is easy to operate and has precise gear switching. The external structure is simple and beautiful, and high-quality components are selected to ensure safe and reliable operation. It is widely used in rural power grids and urban distribution networks.
Three-phase Isolation Transformer
The three-phase isolation transformer is mainly used to isolate the input and output circuits, providing electrical isolation and voltage conversion functions. Rated power (1000VA-1000KVA), input/output voltage (400V/230V), frequency (50Hz/60Hz. It has the characteristics of high efficiency and energy saving, low loss, strong anti-interference ability, and has overload protection and temperature monitoring functions. It is widely used in industrial equipment, data centers, medical equipment, rail transportation and other fields to ensure the safe and stable operation of the power system.
Three-phase Step-up/Step-down Transformer
A three-phase step-up/step-down transformer is a device used to change the three-phase AC voltage, which can increase or decrease the input voltage to the required voltage level. Rated power (usually from several thousand volt-amperes to hundreds of megavolt-amperes), input and output voltage range (such as 400V/11kV), frequency (usually 50Hz or 60Hz) and efficiency (generally above 95%). Due to its low loss, high efficiency, stable operation and durability, it is widely used in power systems, industrial equipment, communication equipment, electrical engineering and substations, etc., and is a key component in power transmission and equipment operation.
What is a three-phase transformer?
A three-phase transformer has the functions of providing a stable three-phase power supply, boosting/reducing voltage to match the power requirements of different equipment, ensuring the efficiency and reliability of the power system, and reducing energy loss during power transmission.
Working principle of three-phase transformer
Main types and application scenarios of three-phase transformers
| Type | Features | Applicable scenarios |
| Dry-Type Transformer | No oil cooling required, environmentally friendly, safe, and easy to maintain | Commercial buildings, data centers, hospitals, subways |
| Oil-Filled Transformer | Better insulation and heat dissipation performance, suitable for high-power applications | Factories, transmission stations, power plants |
| Autotransformer | Small size, low loss, but poor isolation performance | Motor starting, factory equipment |
| Isolation Transformer | Provide electrical isolation and reduce interference | Medical equipment, laboratory instruments |
| Step-Up/Step-Down Transformer | Adjust voltage to match different equipment | Power grid, electric vehicle charging station |
Wiring methods of three-phase transformers
Common wiring methods:
- Y-Y (Wye-Wye) – Applicable to high-voltage transmission, neutral grounding, suitable for light loads.
- Δ-Δ (Delta-Delta) – Applicable to high-power loads, commonly used in motors and welding equipment.
- Y-Δ (Wye-Delta) – Applicable to substations, can achieve step-down conversion.
- Δ-Y (Delta-Wye) – Applicable to step-up systems, usually used for distribution transformers.
How to choose a suitable three-phase transformer?
- Rated power (kVA) – select the transformer power that meets the load requirements.
- Input/output voltage – ensure that the transformer can match the grid and equipment requirements.
- Cooling method – dry type vs. oil-immersed type, depending on the application environment.
- Energy efficiency level – high-efficiency transformers reduce energy consumption and improve long-term cost-effectiveness.
- Insulation level – affects the safety and life of the transformer.
- Product certification – choose products that meet international standards.
Maintenance and common fault troubleshooting of three-phase transformers
- Check the winding temperature to prevent overheating.
- Measure insulation resistance to avoid insulation failure.
- Check the oil level and oil quality (for oil-immersed transformers).
- Tighten the cable connection to prevent looseness and arc faults.
Common Faults and Solutions
| Fault type | Possible cause | Solution |
| Overheating | Overload, poor cooling | Reduce load, check cooling system |
| Excessive noise | Loose, magnetic saturation | Check fasteners, optimize design |
| Insulation breakdown | Moisture, aging | Replace insulation material, keep dry |
Q1: Can a three-phase transformer be used for single-phase loads?
A: Yes, but the load needs to be distributed reasonably to avoid additional losses caused by imbalance.
A: Three-phase transformers are more energy-efficient and have stronger load capacity, making them suitable for industrial and high-power equipment.
A: Choosing an efficient transformer, matching the load reasonably, and regular maintenance can reduce energy consumption.
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