Two Winding Single Phase Oil Immersed ONAN Transformer

The Two Winding Single Phase Oil Immersed ONAN Transformer represents the pinnacle of conventional yet highly reliable power conversion technology. At Lugao Power Co., Ltd., we understand that the backbone of any electrical distribution network lies in the robustness of its transformers. This model is specifically designed to step down or step up voltage between two distinct electrical circuits using a primary and secondary winding configuration, separated by a high-permeability silicon steel core.

The "ONAN" (Oil Natural Air Natural) designation signifies that this unit relies on a natural convection process. The insulating oil circulates naturally as it heats up, transferring thermal energy to the tank walls, which then dissipate into the ambient air. This eliminates the need for external cooling fans or pumps, resulting in a transformer that is not only silent but also significantly less prone to mechanical failure.

Unlike auto-transformers, our Two Winding Single Phase Oil Immersed ONAN Transformer provides complete electrical isolation between the primary and secondary sides. This galvanic isolation is critical for safety, effectively filtering harmonics and protecting sensitive downstream equipment from transient surges. Whether utilized for high-voltage transmission substations or as a service entrance transformer for commercial complexes, this unit guarantees exceptional short-circuit withstand capability and thermal performance.

Product Parameter (Specification)

Lugao Power Co., Ltd. manufactures these units with a high degree of customization to meet specific grid requirements. Below are the standard technical specifications:

Product Feature And Application

Q: Why choose the Two Winding design over an auto-transformer?

1. Provides physical & electrical isolation between HV and LV circuits.

2. Prevents surges (e.g., lightning) from transferring to the secondary side.

3. Essential for safety in residential, industrial control, and medical facilities.

4. Offers better voltage regulation under fluctuating loads.

Q: Why use ONAN cooling instead of forced cooling?

1. No moving parts (no fans, no pumps)--zero risk of auxiliary system failure.

2. Ideal for remote locations with limited maintenance access.

3. Quiet operation--suitable for noise-sensitive environments.

4. Lifespan often exceeds 25 years with minimal intervention.

Q: How does Lugao Power ensure core & winding quality?

1. Uses CRGO silicon steel with step-lap core construction.

2. Reduces no-load losses by nearly 20% vs. standard stacked cores.

3. Windings in high-conductivity copper or aluminum, uniformly wound.

4. Every unit undergoes heat-run and induced overvoltage tests before leaving the factory.

Specific application scenarios

1. Rural Utility Distribution: Extending power lines to agricultural pumps and remote farms.

2. Railway Signaling: Providing reliable power for track-side equipment.

3. Residential Complexes: Stepping down medium voltage to 120V/240V for single-family homes or high-rise building services.

4. Industrial Lighting: Powering heavy-duty industrial lighting grids.

5. Renewable Integration: Coupling with solar inverters to feed isolated single-phase loads.

Production Details

1. Core and Winding Construction

The heart of the Two Winding Single Phase Oil Immersed ONAN Transformer lies in its core. Lugao Power employs a precision-cut, mitered core made from high-permeability CRGO steel. This design minimizes the air gap, significantly reducing magnetizing current and noise. The windings are concentrically placed—the LV winding is positioned closer to the core, with the HV winding wrapped around it. This arrangement optimizes electromagnetic coupling and mechanical strength.

2. Insulation and Tank

We use high-grade transformer oil (Mineral Oil or Natural Ester upon request) that acts as both a dielectric insulator and a cooling medium. The tank is fabricated from heavy-duty steel, coated with a five-step surface treatment process: degreasing, phosphating, priming, intermediate coating, and a final topcoat of UV-resistant paint. This ensures resistance to corrosion in coastal or humid environments.

3. Quality Assurance and Certifications

Every unit is manufactured in compliance with ISO 9001:2015 standards. Our testing protocols include:

1. Routine Tests: Winding resistance measurement, voltage ratio test, no-load loss and current measurement, short-circuit impedance, and dielectric tests.

2. Type Tests: Temperature rise test, lightning impulse test (LI), and short-circuit withstand capability test.

3. We hold certifications that meet global standards such as IEC 60076 and ANSI/IEEE C57.12.00, ensuring our transformers are accepted in international markets.

Why Choose Lugao Power? (Competitor Comparison)

When sourcing a Two Winding Single Phase Oil Immersed ONAN Transformer, the market is saturated with low-cost options that compromise on material quality. Here is why Lugao Power Co., Ltd. stands apart:

Our Commitment: We do not just sell transformers; we provide engineered solutions. Our technical team assists with impedance calculations, tap changer configurations, and installation guidance. With Lugao Power, you receive a Two Winding Single Phase Oil Immersed ONAN Transformer that consistently delivers lower total cost of ownership (TCO) due to reduced maintenance needs and higher energy efficiency.

Application Case Study: Rural Electrification Project

In Q2 of 2024, a municipal utility in Southeast Asia faced frequent failures of imported dry-type transformers due to lightning surges. They switched to Lugao Power’s Two Winding Single Phase Oil Immersed ONAN Transformer units (50 kVA, 11kV/230V).

Results:

1. Reduced Failure Rate: 0% failure rate over two monsoon seasons.

2. Thermal Performance: The ONAN cooling maintained winding temperatures 15°C lower than the previous units under 90% load.

3. Maintenance: The utility reported zero maintenance interventions due to the robust oil preservation system.

Packaging & Shipping

Understanding that logistics can be as critical as manufacturing, Lugao Power ensures that every Two Winding Single Phase Oil Immersed ONAN Transformer is packaged for global transit.

Packaging: Units are shipped filled with high-quality insulating oil. We use wooden crates (ISPM 15 certified) for export or steel frames with protective wrapping. Surge arresters and bushings are packed separately in shock-absorbent foam to prevent transit damage.

Documentation: Each shipment includes a comprehensive manual, test reports, and installation diagrams.

Lead Time: Standard units are available in 20--25 working days. Custom orders require 30--35 days.

Port of Loading: Ningbo.

Frequently Asked Questions (FAQ)

Q1: Can this transformer be used outdoors in extreme temperatures?

A: Absolutely. The ONAN cooling system is designed to handle ambient temperatures ranging from -25°C to +50°C. For extreme environments (desert or arctic), Lugao Power can adjust the oil volume and tank radiator design accordingly. The robust tank coating ensures UV and moisture resistance, making the Two Winding Single Phase Oil Immersed ONAN Transformer ideal for pole-mounting or ground-level outdoor installations.

Q2: What is the typical lifespan of this transformer?

A: With proper installation and periodic oil testing, the operational lifespan is typically between 25 to 30 years. The core and windings are designed with a thermal class that allows for a 30-year insulation life under rated load conditions. Lugao Power offers a standard 5-year manufacturing warranty, with extended service contracts available.

Q3: Do you provide tap changers for voltage regulation?

A: Yes. We offer both Off-Circuit Tap Changers (OCTC) and On-Load Tap Changers (OLTC) depending on the application. For standard distribution, we integrate de-energized taps (+/- 2.5% or 5%) to adjust for grid fluctuations. If you are purchasing a Two Winding Single Phase Oil Immersed ONAN Transformer for sensitive industrial equipment requiring constant voltage, we can install an OLTC system.

Q5: What is the difference between a standard transformer and a "Heavy Duty" variant you offer?

A: Our standard units are built for commercial and general residential use. Our "Heavy Duty" variant of the Two Winding Single Phase Oil Immersed ONAN Transformer features increased copper cross-section, a reinforced core yoke, and a higher grade of insulating oil (Natural Ester) to withstand cyclic overloads of up to 150% for short durations. This is ideal for welding applications, mining equipment, or agricultural loads where starting currents are high.

Contact Lugao Power Co., Ltd. Today

Ensure the continuity of your power network. Choose the durability, efficiency, and safety of our Two Winding Single Phase Oil Immersed ONAN Transformer. For quotes, technical drawings, or bulk order discounts, please use the inquiry form below.