Heavy-duty oil-immersed rectifier transformers are engineered for reliable AC-to-DC power conversion, with a robust industrial light-gray steel enclosure, high-efficiency corrugated cooling fins, and a large oil tank for enhanced thermal stability. Built with eco-friendly, RoHS-compliant materials, including high-grade cold-rolled silicon steel cores and oxygen-free copper windings, these units minimize energy loss and harmonics while meeting IEC 60076 and GB/T 10228 standards. Rated up to 150 MVA (domestic) / 100 MVA (international) with voltage levels from 10kV to 35kV, they support custom winding configurations, voltage ratios, and enclosure designs to match your project needs. Designed for low maintenance and 24/7 continuous operation, these transformers require minimal upkeep and come with full after-sales support, making them ideal for industrial rectification, electrolysis, and power conversion applications worldwide.
As a leading special transformer solution, we provide a specialized power conversion system that transforms AC input into stable, low-ripple DC output—ideal for demanding industrial applications requiring reliable direct current supply.
Going beyond conventional designs, we offer advanced 6-phase and 12-phase configurations that effectively minimize harmonics, boost efficiency, and ensure ultra-stable DC power with minimal voltage fluctuation and electromagnetic interference. These multi-pulse setups reduce harmonic distortion on the power grid while delivering smooth, interference-free output.
These units are widely used across key industries, including electrochemical rectification, steel plant rolling mills, electrostatic precipitators, DC power supply systems, aluminum smelting, and various industrial rectification processes.
They are CE and ISO certified, with 100% factory-tested quality for safety and reliability. We offer competitive pricing without compromising performance, backed by a 12–18 month warranty, fast 2–3 month delivery, and global technical support. Custom solutions are available to meet your unique project requirements.
Product Features
• High-Quality Materials
Premium silicon steel iron core and high-purity oxygen-free copper windings for maximum conductivity and durability.
• Advanced Core Design
Unique silicon steel sheet stacking method that dramatically reduces no-load losses and operating noise.
• Stable DC Output
Extremely low ripple and minimal fluctuation/interference, ensuring clean and reliable DC power—especially with 6-phase and 12-phase designs that further mitigate harmonics.
• Superior Performance
Low losses, low noise, high efficiency, and small temperature rise for energy-saving and quiet operation.
• Multi-Phase Capability
In addition to conventional transformers, we produce 6-phase and 12-phase transformers optimized for smoother waveforms, reduced harmonic distortion, and higher power quality in rectifier systems.
• Robust & Reliable
Designed for continuous heavy-duty service with excellent thermal management and long service life.
These features make our transformers stand out for applications requiring stable, high-power DC conversion with minimal maintenance
Specifications & Parameters
Typical technical parameters – fully customizable to meet specific project needs:
| Category | Specification / Description |
| Ratings | Silicon Steel Transformers – Up to 100 MVA |
| Cooling Methods |
ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), OA |
| Insulating Fluid | Mineral oil to international specifications or Natural oil-based eco-friendly insulating liquid |
| Frequency | 50 Hz / 60 Hz |
| Polarity | As specified by customer |
| Primary Voltage | Up to 35 kV Class |
| Secondary Voltage | 170–860 V (custom voltages available on request) |
| Winding Material | High-quality copper |
| Impedance | In accordance with applicable standards (GB1094, IEC60076, etc.) |
| Phase Configurations | Standard single/3-phase, plus specialized 6-phase and 12-phase transformers for multi-pulse rectification and harmonic reduction. |
| All parameters align with rigorous industry standards, ensuring safe, efficient, and compliant operation applications. | |
Packaging, Warranty & Certifications Packaging：
Secure, export-standard wooden crates or sea-worthy packaging with protective measures against moisture, shock, and vibration during transportation. Custom packaging options available..
Warranty：
Standard 12–18 months warranty (extendable), covering manufacturing defects and performance issues under normal operation. Comprehensive after-sales technical support included.
Certifications & Testing：
Compliant with GB1094, IEC60076, and other relevant international standards. ISO-certified manufacturing processes ensure consistent quality and reliability.
Six-pulse rectifier loads pull current in steps, and those steps travel back down the line as harmonic distortion. In this transformer rectifier the secondary windings are split and deliberately offset, so harmonics produced by one set of windings cancel against another instead of reaching the medium-voltage bus. The result is a smoother DC waveform with far less ripple at the load, less interference on control and instrumentation, and easier compliance where the utility or the plant sets harmonic limits. A 12-phase design goes further than a 6-phase one, so it is usually chosen where the DC load is large or ripple-sensitive, or where grid harmonic limits are tight, while a 6-phase unit suits general industrial rectification. Both are built on the same platform.
Buying a transformer for a project needs more than a catalogue number. Our engineering team works with you from the first enquiry: reviewing your load, duty cycle and grid conditions, then matching the right rectifier or oil-immersed distribution transformer to the application. We support customised and OEM builds, and where certification applies our units are supplied to IEC 60076 and CE/ISO standards. After delivery we stay involved with installation and commissioning guidance and troubleshooting support, backed by warranty and global service.
Yes, both frequencies are available. Frequency is confirmed at the design stage because it shapes the core and winding design, so tell us which supply your plant runs when you send your project data.
ONAN relies on natural oil and air circulation and suits normal load profiles in moderate ambient temperatures. ONAF adds forced air across the cooling surfaces for higher ambient temperatures or heavier duty, and OA is available where a project specifies it. The choice is settled at the design stage from your load profile and site conditions.
Very little. There are no regularly replaced parts, and the work that matters is periodic: oil level and temperature, the condition of the tank and cooling surfaces, bushing cleanliness and terminal tightness. Set the inspection interval against your site's maintenance plan.
Yes. As a power transformer manufacturer we build winding configurations, voltage ratios and enclosure designs to project data rather than to a fixed catalogue. Send the electrical data you have, or the nameplate of the unit being replaced, and our engineers will confirm the design with you.
Standard builds use mineral oil meeting international insulating-oil specifications. Where a project wants a lower environmental risk profile, a natural oil-based eco-friendly liquid can be supplied instead, and both options work with the cooling arrangements offered for this range. The choice is confirmed at the design stage.
Send us the rectifier arrangement that is installed and we will confirm which build matches it, because the phase-shifted secondaries have to suit the bridge that follows. That check happens during design review, so the transformer and the rectifier bridge are treated as one DC supply.
