Eco-friendly copper foil for oil-free dry-type transformer is a key conductive material in dry-type transformer winding manufacturing. With increasingly stringent global requirements for energy conservation and environmental protection, dry-type transformers have been widely applied in power distribution transformer fields due to their fire prevention, explosion-proof, and pollution-free characteristics. Accordingly, copper foil for dry-type transformers also has higher requirements for environmental performance and electrical properties.
I. Technical Characteristics of Copper Foil for Dry-Type Transformer
1.1 Special Requirements for Copper Foil in Dry-Type Transformers
Different from oil-immersed transformers, dry-type transformer windings utilize air self-cooling or air-cooled heat dissipation, with relatively higher operating temperatures. This brings special requirements:
Higher Thermal Class: Dry-type transformer winding temperatures can reach 180°C or even higher, requiring copper foil with better thermal stability.
Excellent Insulation Performance: Dry-type transformer windings are in direct contact with air, requiring copper foil surface insulation coating with strong adhesion, weather resistance, and environmental characteristics.
Good Electrical Performance: Low resistivity and high conductivity ensure transformer operating efficiency.
Environmental Safety: Both materials and production processes must meet environmental requirements.
1.2 Differences from Oil-Immersed Transformer Copper Foil
| Item | Dry-Type Transformer Copper Foil | Oil-Immersed Transformer Copper Foil |
|---|---|---|
| Insulation Method | Air self-cooling/air cooling | Transformer oil cooling |
| Operating Temperature | Max 180-200°C | Max 120-130°C |
| Insulation Coating | Water-based/eco-friendly coating | Oil-based coating or passivation |
| Environmental Requirements | Stricter (RoHS/REACH) | Standard requirements |
1.3 Main Application Areas
- Power distribution dry-type transformer
- Wind/PV boost transformer
- High-rise building transformer
- Railway traction transformer
- Mine explosion-proof transformer
II. Detailed Specifications
2.1 Copper Foil Substrate Requirements
Material: Pure copper C11000 (red copper), copper content ≥ 99.90%
Conductivity: Annealed state IACS ≥ 98%
Thickness Range: 0.1-3.0mm
- Thin gauge: 0.1-0.5mm
- Medium: 0.5-1.5mm
- Thick gauge: 1.5-3.0mm
Width Range: 10-600mm, customizable
2.2 Mechanical Properties
Annealed State (O State):
- Tensile Strength: 200-260MPa
- Elongation: ≥35%
- Hardness: 40-50HV
Semi-Hard State (H04):
- Tensile Strength: 260-320MPa
- Elongation: ≥20%
- Hardness: 50-65HV
Hard State (H06):
- Tensile Strength: ≥320MPa
- Elongation: ≥5%
- Hardness: ≥65HV
2.3 Insulation Coating Requirements
Adhesion: Strong coating adhesion to copper foil substrate, no peeling
Heat Resistance: Thermal class not lower than H class (180°C)
Weather Resistance: Moisture, salt spray, and UV resistance
Environmental: Compliant with RoHS directive and REACH regulation
Electrical Performance: High insulation resistance, breakdown voltage ≥50kV/mm
III. Environmental Characteristics and Certifications
3.1 Environmental Requirements
Material Environmental:
- No lead, cadmium, mercury, or other harmful substances
- Compliant with EU RoHS directive
- Compliant with REACH regulation
Production Process Environmental:
- Eco-friendly surface treatment process
- Wastewater and exhaust gas meeting discharge standards
- Compliant with ISO 14001 environmental management system
Usage Process Environmental:
- No risk of transformer oil leakage
- Flame-retardant, non-combustible
- Recyclable and reusable
3.2 Quality Certifications
ISO 9001, ISO 14001, RoHS, REACH, Product Factory Inspection Report
IV. Selection Guide
4.1 Selection by Voltage Level
| Voltage Level | Thickness Range | Width Range | Recommended State | Insulation Requirement |
|---|---|---|---|---|
| 10kV and below | 0.3-1.5mm | 20-400mm | O/H04 state | F class insulation |
| 10-35kV | 0.5-2.0mm | 30-500mm | H04 state | H class insulation |
| 35kV and above | 0.8-3.0mm | 50-600mm | H04/H06 state | H/C class insulation |
4.2 Selection by Insulation Class
F class (155°C): Suitable for general dry-type transformers, cost-effective
H class (180°C): Suitable for high-temperature environments or high-load dry-type transformers
C class (above 200°C): Suitable for special high-temperature environments or high safety requirements
4.3 Selection by Application
Power Distribution Dry-Type Transformer: Generally H class insulation, F class also acceptable
Wind/PV Transformer: H class recommended due to higher operating temperature
High-Rise Building Transformer: H class recommended, emphasizing fire safety
Railway Traction Transformer: H/C class recommended to meet high reliability requirements
V. Production Process Key Points
5.1 Copper Foil Substrate Production
Using C11000 electrolytic copper plate, through hot rolling, cold rolling, and annealing processes.
Key Control Points: Copper content ≥99.90%, strict impurity control, thickness uniformity
5.2 Eco-Friendly Insulation Coating Treatment
Coating Types:
- Water-based insulation coating: Excellent environmental performance, heat resistance up to H class
- Eco-friendly UV coating: Fast curing speed, good environmental performance
- Inorganic insulation coating: Thermal class up to C class
Coating Process Control: Coating thickness uniformity, curing temperature and time, coating adhesion
5.3 Quality Inspection
Each batch inspection: thickness, width, length, mechanical properties, conductivity, insulation coating thickness, insulation resistance, breakdown voltage, adhesion test
VI. Quality Inspection Methods
6.1 Routine Inspection Items
Dimensional: Thickness (micrometer, 0.001mm accuracy), Width (vernier caliper, 0.02mm accuracy), Length
Appearance: Surface defects (scratches, indentations, oxide spots), Coating quality (bubbles, peeling, uneven thickness)
6.2 Performance Inspection
Mechanical: Tensile strength, elongation (universal testing machine), Hardness (Vickers hardness tester)
Electrical: Conductivity (eddy current conductivity meter), Insulation resistance (megohmmeter), Breakdown voltage (tester)
Environmental: RoHS and REACH substance testing
6.3 Storage and Transportation
Storage: Dry, ventilated warehouse, humidity ≤60%, avoid corrosive substances, direct sunlight, heavy pressure and impact
Transportation: Moisture-proof, rain-proof, impact-proof, coating surface facing up, clearly labeled
VII. Supplier Selection Recommendations
7.1 Key Evaluation Points
- Environmental Certification: RoHS, REACH, ISO 14001 certifications
- Insulation Coating Technology: Mature coating technology, eco-friendly coating
- Testing Capability: Complete environmental performance testing reports
- Delivery Capability: Stock of standard specifications
- Technical Support: Selection advice and technical services
7.2 Sample Testing
Conduct before bulk purchase: dimensional inspection, appearance inspection, performance testing, insulation testing, environmental testing
7.3 Price Considerations
Copper price fluctuation, insulation coating type, specification precision, order quantity. Choose reasonable price-performance ratio while ensuring quality.
VIII. Common Specifications Reference
8.1 Power Distribution Dry-Type Transformer Copper Foil
| Thickness | Width | State | Insulation Class | Width Tolerance | Applications |
|---|---|---|---|---|---|
| 0.3mm | 50-200mm | O state | F/H class | ±0.05mm | Low voltage winding |
| 0.5mm | 50-300mm | H04 | H class | ±0.08mm | Medium voltage winding |
| 0.8mm | 50-400mm | H04 | H class | ±0.10mm | High voltage winding |
| 1.0mm | 100-400mm | H04 | H class | ±0.10mm | High voltage winding |
8.2 Special Dry-Type Transformer Copper Foil
| Thickness | Width | State | Insulation Class | Width Tolerance | Applications |
|---|---|---|---|---|---|
| 0.2mm | 20-100mm | O state | H class | ±0.03mm | High frequency transformer |
| 0.5mm | 50-200mm | H04 | C class | ±0.05mm | High temperature transformer |
| 1.5mm | 100-500mm | H06 | H class | ±0.15mm | Large transformer |
Conclusion
Our company has 30 years of experience in exporting magnetic wire and metal foil. We specialize in eco-friendly copper foil for dry-type transformers with copper content ≥99.90%. Insulation classes cover F (155°C), H (180°C), and C (above 200°C), compliant with RoHS and REACH requirements. Thickness range: 0.1-3.0mm. Width range: 10-600mm. Customization available. Standard specifications in stock with fast delivery. Samples shipped globally.
Contact our technical team for selection support.
Contact Information:
Email: office@cnlpzz.com
WhatsApp: 0086-19337889070