Class 240 High-Temperature Enameled Wire for Demanding Applications
As electrical motors and electromagnetic devices operate under increasingly extreme conditions — higher power density, elevated operating temperatures, and more aggressive environments — the demand for high-temperature enameled wires has grown significantly. Among these, Class 240 aromatic polyimide enameled wires represent the highest thermal class available in the industry.
This article provides an in-depth look at Class 240 enameled wires, including their material composition, key performance characteristics, applications, and why they are the preferred choice for mission-critical applications.
1. Why Class 240?
Enameled wire thermal classes are defined by their maximum continuous operating temperature. The higher the class, the greater the thermal margin available to the motor designer.
| Thermal Class | Max. Operating Temp. (°C) | Typical Insulation Material | Common Applications |
|---|---|---|---|
| Class 155 | 155 | Polyester / Polyurethane | Small motors, transformers, consumer goods |
| Class 180 | 180 | Polyester-imide | Industrial motors, power tools |
| Class 200 | 200 | Polyamide-imide composite | EV motors, high-performance servo |
| Class 220 | 220 | Polyimide | Aerospace, high-speed motors |
| Class 240 | 240 | Aromatic Polyimide | Extreme environments, military, VCM |
※ Temperature limits are based on IEC 60317 and GB/T 6109 standards.
Class 240 aromatic polyimide offers the highest thermal endurance among all organic insulating materials. Its unique molecular structure provides exceptional resistance to thermal degradation, oxidation, and radiation — making it the material of choice for applications where failure is not an option.
2. CHINGCUNG Class 240 Enameled Wire Series
CHINGCUNG offers a comprehensive range of Class 240 enameled wires in round and rectangular profiles, with copper, aluminum, and copper-clad aluminum conductor options.
2.1 Round Wires
| Model Number | Conductor Material | Diameter Range (mm) | Thermal Class | Film Grade | Key Feature |
|---|---|---|---|---|---|
| QY-1/240 | Copper | 0.06 – 0.90 | 240 | 1 | Standard polyimide |
| QY-2/240 | Copper | 0.06 – 0.90 | 240 | 2 | Heavy polyimide build |
| QY-3/240 | Copper | 0.06 – 0.90 | 240 | 3 | Triple insulation layer |
| QYL-1/240 | Aluminum | 0.14 – 1.20 | 240 | 1 | Lightweight alternative |
| QYL-2/240 | Aluminum | 0.14 – 1.20 | 240 | 2 | Heavy build on aluminum |
| CCAQY-1/240 | CCA | 0.17 – 0.90 | 240 | 1 | Cost-effective solution |
| CCAQY-2/240 | CCA | 0.17 – 0.90 | 240 | 2 | Enhanced mechanical strength |
2.2 Rectangular Wires (for Hairpin Motors & High-Power Applications)
| Model Number | Conductor Material | Cross-Section (mm²) | Thermal Class | Film Grade | Application |
|---|---|---|---|---|---|
| PIW-1/240 | Copper | 0.0125 – 25 | 240 | 1 | Standard flat wire |
| PIW-2/240 | Copper | 0.0125 – 25 | 240 | 2 | Heavy build flat wire |
| PIW-3/240 | Copper | 0.0125 – 25 | 240 | 3 | Triple insulation flat wire |
| PIW(CR)-1/240 | Copper | 0.0125 – 25 | 240 | 1 | Corona-resistant for inverter drives |
| PIW(CR)-2/240 | Copper | 0.0125 – 25 | 240 | 2 | Corona-resistant with heavy build |
※ Custom cross-sections and dimensions are available upon request.
3. Performance Comparison: Class 240 vs. Lower Thermal Classes
💡 Key Insight: The primary advantage of Class 240 lies not just in its higher temperature rating, but in its superior thermal aging resistance. At the same operating temperature, Class 240 wires can deliver significantly longer service life compared to Class 200 or Class 180 materials.
| Property | Class 180 (Polyester-imide) | Class 200 (PAI Composite) | Class 240 (Aromatic Polyimide) |
|---|---|---|---|
| Max. Continuous Temp. | 180°C | 200°C | 240°C |
| Cut-through Temperature | 300°C | 320°C | 450°C |
| Heat Shock (°C) | 200°C | 220°C | 260°C |
| Relative Thermal Life at 200°C | ~5,000 hrs | ~10,000 hrs | > 20,000 hrs |
| Radiation Resistance | Poor | Moderate | Excellent |
| Chemical Resistance | Good | Good | Excellent |
※ Typical values based on IEC 60317 and GB/T 6109 standard test methods.
4. Typical Applications
Class 240 enameled wires are specified in applications where thermal, mechanical, or environmental stresses exceed the limits of lower-class materials.
- Voice Coil Motors (VCM) — Camera autofocus actuators, hard disk drives, and optical devices requiring precision and reliability at elevated temperatures.
- Aerospace & Defense — Actuators, solenoids, and sensors in aircraft engines, avionics, and space systems where thermal cycling and radiation are concerns.
- Electric Vehicle Traction Motors — Hairpin wound stators operating at high power density with limited cooling capacity.
- High-Speed Spindles — Machine tool spindles and turbo-compressors where centrifugal force and temperature rise are critical design factors.
- Oil & Gas Equipment — Downhole motors and sensors operating in high-temperature environments (150°C+ ambient).
- Medical Devices — Sterilizable instruments where exposure to repeated autoclave cycles (up to 135°C) is required.
5. Quality & Standards Compliance
All CHINGCUNG Class 240 enameled wires are manufactured in ISO 9001 and IATF 16949 certified facilities, with rigorous in-process and final testing to ensure compliance with international standards.
- GB/T 6109.6-2008 — Enamelled round winding wires, Class 220
- GB/T 6109.22-2008 — Enamelled round winding wires, Class 240
- IEC 60317-7: 1997 — Enamelled round copper wire, Class 220
- IEC 60317-46: 1997 — Enamelled round copper wire, Class 240
6. Why Choose CHINGCUNG Class 240 Enameled Wires?
With over 10 years of experience in specialty enameled wire manufacturing, CHINGCUNG delivers Class 240 products that combine:
- Proven thermal performance — Verified by third-party testing to meet or exceed IEC and GB/T requirements.
- Reliable supply chain — 100-ton monthly capacity with stable, consistent quality.
- Application support — Engineering assistance for wire selection and motor design optimization.
- Global availability — Serving customers in Europe, North America, and Russia with efficient logistics.
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