High purity copper foil for air core reactors is a key conductive material in air core reactor winding manufacturing. Air core reactors are special reactors without iron cores, using air as part of the magnetic circuit. They feature excellent linear characteristics, no magnetic saturation, low loss, and low noise, widely used in high-voltage transmission systems, harmonic treatment, reactive power compensation, industrial power supplies, and other fields.
I. Working Characteristics of Air Core Reactors
Air core reactors adopt an air-core coil structure without an iron core. Their working characteristics are as follows:
Operating frequency covers a wide range, from 50Hz power frequency to several kHz high frequency. Excellent linear characteristics with inductance value unchanged regardless of current magnitude. No magnetic saturation phenomenon with strong short-circuit current withstand capability. Good heat dissipation with air natural cooling or forced air cooling. No iron core loss with low operating noise.
Core functions include: limiting short-circuit current, filtering and harmonic treatment, reactive power compensation, and series current limiting in high-voltage transmission lines.
II. Four Requirements for Copper Foil Materials
First, extremely high conductivity. Copper content ≥99.95%, conductivity IACS ≥101%, reducing copper loss, minimizing temperature rise, and improving reactor efficiency.
Second, excellent mechanical properties. Withstand electromagnetic mechanical stress during operation, including vibration during normal operation and huge impact forces during short-circuit faults.
Third, good heat resistance. Copper foil temperature may rise under high-frequency or high-current conditions, requiring materials with excellent thermal stability.
Fourth, reliable dimensional accuracy. Air core reactor inductance is precisely related to winding turns; thickness and width accuracy directly affect electrical parameters.
III. Detailed Explanation of Parameters
3.1 Copper Foil Substrate
- Material: High purity red copper, copper content ≥99.95%
- Conductivity: Annealed state IACS ≥101%
- Thickness Range: 0.1-5.0mm
- Width Range: 10-800mm
3.2 Mechanical Property Parameters
O State (Annealed): Tensile strength 200-260MPa, elongation ≥40%, hardness 40-50HV
H04 State (Semi-hard): Tensile strength 260-320MPa, elongation ≥20%, hardness 50-65HV
H06 State (Hard): Tensile strength ≥320MPa, elongation ≥5%, hardness ≥65HV
3.3 Characteristics of High Purity Copper Foil
Compared with ordinary C11000 copper foil, high purity copper foil offers:
- Higher conductivity: IACS ≥101%, more than 3% higher than ordinary copper foil (98%)
- Lower impurity content: Extremely low iron, sulfur, and other impurity elements
- Better ductility: Elongation can reach ≥40% in annealed state
- Superior corrosion resistance: Less impurity, better chemical stability
IV. Selection Guide
4.1 Selection by Power Rating
| Power Rating | Recommended Thickness | Recommended Width | Recommended State |
|---|---|---|---|
| Small Power (<10kVar) | 0.2-0.5mm | 20-80mm | O-state |
| Medium Power (10-100kVar) | 0.3-1.0mm | 50-150mm | O-state or H04-state |
| Large Power (100-500kVar) | 0.5-2.0mm | 80-300mm | H04-state |
| Ultra-Large Power (>500kVar) | 1.0-5.0mm | 150-800mm | H04-state or H06-state |
4.2 Selection by Insulation Class
General insulation: O-state annealed copper foil, surface insulation treatment
Higher insulation: H-class insulating coating, heat resistance 180°C
4.3 Selection by Application Scenario
High-voltage transmission series reactor: High insulation required, recommend H-class insulated copper foil
Industrial harmonic treatment reactor: Good heat dissipation required, recommend H04-state copper foil
Reactive power compensation reactor: Focus on electrical performance, recommend high purity O-state copper foil
High-frequency filter reactor: Consider skin effect, select thinner specifications
V. Differences from Iron Core Reactor Copper Foil
| Item | Air Core Reactor Copper Foil | Iron Core Reactor Copper Foil |
|---|---|---|
| Conductivity Requirement | IACS ≥101% | IACS ≥98% |
| Purity Requirement | ≥99.95% | ≥99.90% |
| Mechanical Properties | Higher (greater electromagnetic force) | General |
| Insulation Class | Usually higher | General |
VI. Dimensional Tolerance Requirements
Thickness tolerance: Standard ±0.02mm, High precision ±0.01mm, Ultra-high precision ±0.005mm
Width tolerance: Standard ±0.3mm, High precision ±0.1mm, Ultra-high precision ±0.05mm
VII. Key Points of Production Process
7.1 High Purity Copper Foil Substrate Production
High purity electrolytic copper plate → special smelting and casting → hot rolling → cold rolling → annealing
Key Control Points: Copper content ≥99.95%, extremely low impurity content, thickness uniformity ±0.01mm, smooth surface, burr-free edges
7.2 Insulation Coating Treatment
- Ordinary insulation: anti-oxidation + basic insulation
- H-class insulation: heat resistance 180°C
- Special insulation: customized per requirements
7.3 Precision Slitting and Forming
Width tolerance per precision requirements, edges neat and burr-free, length customized
VIII. Quality Inspection Methods
8.1 Dimensional Inspection
Thickness: electronic micrometer (0.001mm accuracy); Width: projector/vernier caliper; Length: steel tape measure
8.2 Appearance Inspection
Surface: scratches, indentations, oxide spots; Edge: burrs, rough edges
8.3 Performance Testing
Mechanical: universal testing machine; Electrical: eddy current conductivity meter (IACS ≥101%); Chemical: spectrometer (copper content ≥99.95%)
IX. Supplier Selection Recommendations
Key points: Material purity, conductivity indicators, specifications range, testing capability, technical support
Sample testing process: Chemical analysis → Conductivity test → Mechanical property test → Winding suitability test
X. Commonly Used Specifications
| Thickness | Width Range | State | Typical Applications |
|---|---|---|---|
| 0.3mm | 30-80mm | O-state | Small power air core reactors |
| 0.5mm | 50-120mm | O-state | Medium power air core reactors |
| 0.8mm | 80-200mm | H04-state | Large power air core reactors |
| 1.0mm | 100-250mm | H04-state | Large power air core reactors |
| 1.5mm | 150-350mm | H04-state | Ultra-large power air core reactors |
| 2.0mm | 200-400mm | H04-state | Industrial grade air core reactors |
| 3.0mm | 300-600mm | H04 or H06 | Giant power air core reactors |
XI. Conclusion
Our company has 30 years of experience in exporting electrical wire and metal foil, specializing in high purity copper foil for air core reactors.
Core advantages:
- High purity red copper, copper content ≥99.95%, conductivity IACS ≥101%
- Thickness range 0.1-5.0mm, width range 10-800mm
- Thickness tolerance ±0.01mm, width tolerance ±0.1mm
- Each batch comes with conductivity, mechanical property, and chemical composition test reports
- Customized specifications and insulation treatment available
- Samples and small batch orders shipped globally
Contact our technical team for selection support.
Contact Information:
Email: office@cnlpzz.com
WhatsApp: 0086-19337889070