Your Leading Transformer Manufacturer
A welding transformer converts high-voltage grid power into the low-voltage, high-current energy required to fuse metals instantly. As a transformer manufacturer with 16+ years of experience,By utilizing 100% pure copper and premium magnetic cores, Haifei transformers maximize this electrical induction while minimizing heat loss. Our advanced VPI insulation and integrated water-cooling ensure the unit remains stable and safe during 24/7 heavy-duty operation, providing the consistent power output necessary for high-precision automated welding.
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DC TransformerOur DC Transformer (HDC Series) is a high-performance power electronic device designed for precision voltage transformation via high-frequency inversion and isolation. Unlike a traditional AC...view more
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Flash Butt Welding TransformerThe Flash Butt Welding Transformer is the core power component of flash butt welding machines. It efficiently converts high-voltage AC into the low-voltage, high-current power required for flash...view more
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Secondary Rectification TransformerHaifei’s Secondary Rectification Transformers (DC & BTDC Series) are engineered for high-precision resistance welding. By delivering a stable, low-ripple DC output, our transformers significantly...view more
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AC TransformerThe BSAC series AC Transformer is the core energy unit in resistance welding systems, specifically designed for AC spot welding and projection welding machines. This series utilizes a...view more
Why Choose Us
Rich Experience
Founded in 2009, Haifei has grown from a small business to a world-renowned welding equipment manufacturer. The customer-centric, win-win cooperation philosophy makes the company more mature and powerful.
Production Capacity
Our modern 10,000 m² production facility and team of 100+ engineering specialists enable us to deliver innovative, high-performance welding solutions to industries worldwide.
Production Market
Haifei has more than 40,000 successful welding application cases, with customers in Europe, North America, Southeast Asia, India, and other regions.
24H Online Service
If you encounter difficulties in using the product, we will respond to your needs as soon as possible and provide you with the greatest support.
Working Principle of Welding Transformers
Welding transformers operate based on the principle of electromagnetic induction. They convert high-voltage, low-current input into low-voltage, high-current output, which generates resistance heat at the workpiece contact points, thereby achieving material fusion.
During welding, current flows through the workpiece contact surface. Due to the contact resistance, instantaneous high temperatures are generated, causing the material to locally melt and form a strong weld joint.
The Role of Welding Transformers in Resistance Welding
Welding transformers not only provide the current required for welding, but also directly affect:
- Weld strength and consistency
- Stability of the welding process
- Energy efficiency
A stable transformer can effectively reduce welding defects and improve overall production efficiency.




Key Features and Advantages of Our Welding Transformers
Highly Stable Current
Output
Optimized electromagnetic design and winding structure effectively reduce current fluctuations, ensuring stable welding processes and improving weld consistency.
01
Highly Efficient and Energy-Saving Design
Utilizing low-loss magnetic materials and optimized structural design reduces energy loss and improves overall equipment energy efficiency.
02
Superior Core
Materials
High-permeability silicon steel sheets and high-purity copper windings ensure long-term stable operation and extend equipment lifespan.
03
Suitable for Multiple Welding Processes
Widely applicable to spot welding, projection welding, butt welding, and automated welding systems, adaptable to various industrial scenarios.
04
Customized Design
Support
Customized services are available for power, structural dimensions, and installation methods based on different customer welding process requirements.
05
Comparison of Welding Transformer Types
DC Welding Transformer vs. AC Welding Transformer
DC welding transformers offer more stable output current and higher weld consistency, making them suitable for applications requiring high welding quality. AC welding transformers have a simpler structure and lower cost, suitable for general welding needs.
Medium Frequency DC vs. Secondary Rectifier Transformers
Medium frequency DC systems offer higher control precision and more concentrated energy output. Secondary rectifier transformers are more compact in structure, suitable for integration into specific equipment.
Features of Flash Butt Welding Transformers
Flash butt welding transformers possess instantaneous high current output capability, suitable for butt welding of large cross-section metal workpieces, and widely used in processes such as steel joining.
Summary of Applicable Scenarios for Different Transformer Types
Different types of transformers are suitable for different working conditions, such as thin plate welding, thick plate welding, high-strength materials, and automated production lines. The appropriate type should be selected based on specific requirements.
DC & BTDC Series Secondary Rectification Transformer

| Single-phase Secondary Rectification Transformer (DC) | ||||||
|
MODEL |
Rate Power |
Primary Power |
Duty Cycle |
Rated Input Current |
Secondary No-load Voltage |
Short Circuit Current |
|
DC-25 |
25 KVA |
380 KVA 50HZ |
50% |
66A |
4V |
20KA |
|
DC-63 |
63 KVA |
380 KVA 50HZ |
50% |
131 A |
6.8 V |
30 KA |
|
DC-100 |
100 KVA |
380 KVA 50HZ |
50% |
197 A |
7.3V-9.5 V |
38 KA |
|
DC-160 |
160 KVA |
380 KVA 50HZ |
50% |
263 A |
9.5-11.8 V |
46 KA |
|
DC-200 |
200 KVA |
380 KVA 50HZ |
50% |
328 A |
10.5-12.6 V |
53 KA |
|
DC-250 |
250 KVA |
380 KVA 50HZ |
50% |
421 A |
10.8-13.6 V |
58 KA |
| Three-phase Secondary Rectification Transformer (BTDC) | ||||
|
MODEL |
Primary Power |
Duty Cycle |
Secondary No-load Voltage |
Short Circuit Current |
|
BTDC-3*100 |
380 KVA 50HZ |
50% |
7.3V-9.5V |
66 KA |
|
BTDC-3*160 |
380 KVA 50HZ |
50% |
9.5V-11.8V |
90 KA |
|
BTDC-3*200 |
380 KVA 50HZ |
50% |
10.5V-12.6V |
110 KA |
|
BTDC-3*250 |
380 KVA 50HZ |
50% |
10.8V-13.6V |
125 KA |
BSAC Series AC Transformer

|
MODEL |
Rate Power |
Primary Power |
Duty Cycle |
Rated Input Current |
Secondary No-load Voltage |
Short Circuit Current |
|
BSAC-25 |
25 KVA |
380 KVA 50HZ |
50% |
66A |
4V |
20KA |
|
BSAC-50 |
50 KVA |
380 KVA 50HZ |
50% |
131 A |
6.4 V |
26 KA |
|
BSAC-75 |
75KVA |
380 KVA 50HZ |
50% |
197 A |
7.3 V |
30 KA |
|
BSAC-100 |
100 KVA |
380 KVA 50HZ |
50% |
263 A |
8 V |
35 KA |
|
BSAC-125 |
125 KVA |
380 KVA 50HZ |
50% |
328 A |
8.8 V |
40 KA |
|
BSAC-160 |
160 KVA |
380 KVA 50HZ |
50% |
421 A |
10 V |
46 KA |
|
BSAC-200 |
200 KVA |
380 KVA 50HZ |
50% |
526 A |
10.8 V |
53 KA |
|
BSAC-250 |
250 KVA |
380 KVA 50HZ |
50% |
657 A |
11.8 V |
58 KA |
|
BSAC-300 |
300 KVA |
380 KVA 50HZ |
50% |
921 A |
12.7 V |
63 KA |
|
BSAC-400 |
400 KVA |
380 KVA 50HZ |
50% |
1052 A |
11V - 16V |
72 KA |
DH Series Flash Butt Welding Transformer

|
MODEL |
Rate Power |
Primary Power |
Duty Cycle |
Rated Input Current |
Secondary No-load Voltage |
|
DH-200 |
200 KVA |
380 KVA 50HZ |
50% |
526A |
4V - 10V |
|
DH-400 |
400 KVA |
380 KVA 50HZ |
50% |
1053 A |
5.5V - 9.5V |
|
DH-600 |
600 KVA |
380 KVA 50HZ |
50% |
1578 A |
5.8V - 11.8V |
|
DH-800 |
800 KVA |
380 KVA 50HZ |
50% |
2105 A |
6.3V - 12.6V |
|
DH-1000 |
1000 KVA |
380 KVA 50HZ |
50% |
2631 A |
6.8V - 13.6V |
|
DH-1250 |
1250 KVA |
380 KVA 50HZ |
50% |
3289 A |
7.3V - 14.6V |
DC Transformer



|
MODEL |
Primary Power |
Niminal power at 20% D.C |
Short Circuit Current |
Secondary Non-load Voltage |
Turns Ratio |
Cooling Water Flow |
Insulation Class |
Weight |
|
HDC-5075 |
500 V 1000 Hz |
90 KVA |
22 KA |
8.4 V |
60 : 1 |
8 L/ min |
Grade F |
13.8 kg |



|
MODEL |
Primary Power |
Niminal power at 20% D.C |
Short Circuit Current |
Secondary Non-load Voltage |
Turns Ratio |
Cooling Water Flow |
Insulation Class |
Weight |
|
HDC-5076 |
500 V 1000 Hz |
90 KVA |
22 KA |
8.4 V |
60 : 1 |
8 L/ min |
Grade F |
13.8 kg |
Remark: Parallel output mode for all types of Mid-Frequency transformers, can change it according to the installation size required by the customer.

How to Choose the Right Welding Transformer ?
When selecting a welding transformer, it's crucial to consider factors such as welding process, material properties, production requirements, and power supply conditions, rather than focusing solely on a single parameter.
Welding Process and Material Factors
Different welding processes (spot welding, projection welding, butt welding, etc.) have different requirements for current output characteristics. Simultaneously, the conductivity and thickness of the material directly affect transformer selection.
Power and Power Supply Matching
The transformer capacity needs to match the actual welding requirements, satisfying the maximum welding current demand while avoiding increased costs due to over-configuration. The factory's power supply conditions must also be considered to ensure stable equipment operation.
Equipment Structure and Application
Select the appropriate structure based on the production method, such as stationary equipment or an automated integrated system. Future expansion needs should also be considered to enhance the long-term value of the equipment.
Stability and Maintenance Factors
A high-quality welding transformer should possess stable electrical performance and excellent heat dissipation design, and be easy to maintain to ensure long-term reliable operation.
Based on this information, Haifei Intelligent Equipment Co., Ltd. can recommend cost-effective and stable welding transformer solutions for you.
Operating Instructions and Safety Precautions
Installation and Wiring Requirements
Connect the power supply and cooling system according to specifications to ensure safe operation of the equipment.
Pre-use
Inspection
Check the insulation condition, wiring tightness, and cooling system operation to avoid abnormal operation.
Operating Precautions
Avoid prolonged overload operation to prevent overheating, which could affect performance and lifespan.
Daily Maintenance Recommendations
Regularly inspect electrical connections and keep the cooling system clean to improve equipment stability.
Ordering Process
Send Us Inquiry → Receive Our Quotation → Negotiate Details → Confirm the Sample → Sign Contract/Deposit → Mass Production →Cargo Ready → Balance/Delivery → Further Cooperation
Certificate



Payment Terms
T.T with 30% downpayment, 70%before shipment.
Paypal or West Union also accept.
Packaging & Shipping

FAQ
Q: How to choose a welding transformer with appropriate power?
A: A comprehensive evaluation should be conducted based on material thickness, welding process, and maximum current requirements.
Q: What are the causes of welding transformer overheating?
A: It may be related to overload operation, abnormal cooling system, or poor wiring.
Q: Do you support customization? What is the lead time?
A: Customization is supported. The specific lead time depends on product specifications and order details.
We're well-known as one of the leading transformer manufacturers and suppliers in China. Please rest assured to buy high quality transformer made in China here from our factory. For price consultation, contact us.
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