Resistance Welding Transformer

The resistance welding transformer is the core power supply unit of resistance welding machines, delivering high energy through the principle of resistive heating. Compared to standard power transformers, it features specialized construction and electrical characteristics optimized for resistance welding processes. Rated capacity typically exceeds 50kVA, with secondary-side operating currents reaching 2000 to 40,000A. Widely used in spot welding, seam welding, and butt welding applications across automotive manufacturing, steel drum production, and household appliance industries.

1. Ultra-High Current Output with Low-Voltage Design

Resistance welding generates heat through contact resistance at the workpiece joint. Since welding circuit resistance is typically in the micro-ohm (μΩ) range, substantial current is required to produce sufficient heat. This transformer series delivers secondary currents from 2000 to 40,000A, meeting the welding requirements of various metal materials.

Secondary voltage is extremely low: fixed welders typically operate below 10V, while portable (suspension) welders, due to longer welding circuits, operate at approximately 24V. This low-voltage design ensures operational safety while concentrating energy precisely at the weld zone.

2. Streamlined Winding Structure with Flexible Power Adjustment

The secondary winding features only 1–2 turns (2 turns for suspension or long-arm welders), minimizing internal impedance for efficient high-current delivery. With fixed secondary turns, power regulation is achieved by varying primary winding turns, offering 4–12 adjustment levels to accommodate various material types and thicknesses.

3. Robust Cooling Design for Intermittent Operation

Resistance welding transformers operate in an intermittent duty cycle-power is not applied during workpiece loading/unloading, clamping, positioning, or the pre-pressure, forging, and dwell stages of the welding cycle. This naturally provides cooling intervals. For high-power models, water-cooled construction is employed, with cooling water pipes embedded in the secondary winding. Primary and secondary windings are interleaved so that the water-cooled secondary also helps dissipate heat from the primary.

4. High-Quality Core and Insulation Materials

The core is constructed from cold-rolled oriented high-grade silicon steel laminations in a shell-type configuration, delivering high magnetic circuit efficiency. Insulation meets Class F thermal rating, ensuring long-term reliability under high-temperature, high-current operating conditions. Transformer impedance is below 10⁻³Ω, minimizing internal losses.

5. High Reliability in Demanding Environments

The product operates reliably at altitudes up to 2000m, ambient temperatures up to 40°C, and relative humidity up to 90%. Robust housing construction ensures stable long-term operation in industrial environments with minimal vibration and no corrosive gases.

Spot Welders: Automotive body welding, sheet metal joining

Seam Welders: Steel drum manufacturing, sealed container production

Butt Welders: Bar and tube joining

Suspension (Portable) Welders: Large workpieces, hard-to-reach welding positions

Portable Welding Guns: On-site maintenance, flexible operations

Standard products and custom designs available

Custom winding parameters and power tap configurations based on material type and thickness

12-month machine warranty with lifetime maintenance

24/7 remote technical support and on-site service