Polyester base
Better adhesion and softening-breakdown (cut-through) performance; the more economical option.
Enamelled winding wire
Class 200 Polyester / Polyamide-Imide Enamelled Aluminium Wire
Dual-coat enamelled aluminium wire has a polyester or polyesterimide base coat overcoated with polyamide-imide (PAI), giving a thermal class of 200 together with a hard, slippery, chemically resistant surface. It is the choice for heavy-duty motors, hermetic compressors and automated winding where film damage must be avoided. Metline supplies it to IEC 60317-25 in grade 1 and 2 builds, worldwide.
- Thermal class
- 200 °C
- Insulation
- PE or PEI base + PAI overcoat
- Diameter
- 0.25 – 5.0 mm
- Standard
- IEC 60317-25
Why a two-layer enamel?
No single affordable resin gives the best adhesion, flexibility, heat resistance and surface toughness at once. Dual-coat wire combines a base coat chosen for adhesion and dielectric strength with a thin polyamide-imide topcoat chosen for toughness and chemical resistance.
The base coat, typically THEIC-modified polyester or polyesterimide, makes up most of the film thickness. The polyamide-imide overcoat is a smaller fraction of the build, but it lifts the temperature index of the whole system to 200, improves cut-through and heat-shock performance, and gives a hard, low-friction surface that resists scratching in high-speed winders and slot insertion machines.
IEC 60317-25 covers this construction on round aluminium conductors. The conductor itself is annealed electrical aluminium (1060, 1070 or 1350-type) in the O temper, the same as for single-coat wires.
Polyesterimide base
Better resistance to overload, heat ageing and blistering in high-temperature refrigerants.
PAI overcoat
Hardness, scratch resistance, solvent and refrigerant resistance; lifts the system to class 200.
Key properties and test values
| Nominal diameter (mm) | Grade 1: mean scratch force (N) | Grade 1: each test (N) | Grade 2: mean (N) | Grade 2: each test (N) |
|---|---|---|---|---|
| 0.40 | 1.95 | 1.65 | 3.15 | 2.65 |
| 0.50 | 2.25 | 1.90 | 3.60 | 3.05 |
| 0.63 | 2.55 | 2.20 | 4.15 | 3.50 |
| 0.80 | 2.95 | 2.50 | 4.75 | 4.05 |
| 1.00 | 3.40 | 2.90 | 5.45 | 4.60 |
| 1.25 | 3.95 | 3.35 | 6.25 | 5.25 |
| 1.60 | 4.60 | 3.90 | 7.15 | 5.85 |
| 2.00 | — | — | 8.20 | 6.95 |
| 2.50 | — | — | 9.30 | 7.90 |
| Nominal diameter (mm) | Minimum elongation | Minimum tensile strength |
|---|---|---|
| up to 0.400 | 10 % | 90 N/mm² |
| 0.400 – 1.000 | 12 % | 90 N/mm² |
| 1.000 – 2.000 | 15 % | 80 N/mm² |
| 2.000 – 5.000 | 15 % | 70 N/mm² |
| Nominal diameter (mm) | Breakdown voltage, grade 1 (V rms, min.) | Breakdown voltage, grade 2 (V rms, min.) |
|---|---|---|
| 0.250 | 2,100 | 3,900 |
| 0.315 | 2,200 | 4,100 |
| 0.400 | 2,300 | 4,400 |
| 0.500 | 2,400 | 4,600 |
| 0.630 | 2,600 | 4,800 |
| 0.800 | 2,600 | 4,900 |
| 1.000 – 2.500 | 2,700 | 5,000 |
Indicative minimums for enamelled round aluminium wire; the edition of IEC 60317-25 or the customer specification on the order governs acceptance.
Sizes and packing
Supply range
- Conductor
- 1060 / 1070 / 1350-type aluminium, O temper
- Diameter
- Grade 1: about 0.25 – 1.60 mm; grade 2: about 0.25 – 5.0 mm
- Diameter tolerance
- Per IEC 60317-0-3, e.g. ±0.005 mm at 0.50 mm and ±0.010 mm at 1.00 mm
- Spools
- Plastic or wooden spools with 150, 200 or 300 mm inner bore options, or payoff drums
- Documents
- Lot test report covering dimensions, elongation, breakdown, scratch, heat shock and pinholes
Application notes and precautions
- Moisture in sealed systems: ester-based films can hydrolyse when moisture is trapped in hermetic or encapsulated windings; dry thoroughly before sealing.
- Chlorine-containing materials: keep away from PVC, neoprene and chloride-bearing salts, which attack the film at temperature.
- Refrigeration compressors: although the insulation is class 200, aluminium windings in hermetic compressors are usually limited to around 130 °C operating temperature, and the wire must be qualified with the specific refrigerant and oil.
- High-overload motors: aluminium's lower conductivity means higher current density for a given slot; for motors with severe short-term overloads or continuous high power density, check temperature rise carefully or consider copper.
- Varnish: compatible with most impregnating varnishes; confirm with a bond-strength test for new combinations.
Typical applications
Heavy-duty motors
Industrial motors, traction auxiliaries and pumps that run hot or are wound and inserted by machine.
Compressors
Refrigeration and air-conditioning compressor motors, subject to refrigerant qualification.
Transformers
Dry-type and oil-filled transformers where higher thermal margin extends life.
Appliances and tools
Washing-machine, dishwasher and power-tool motors where winding damage must be minimised.
Class 200 compared with single-coat wires
| Feature | Polyester (130/155) | Polyesterimide (180) | Dual coat PE/PEI + PAI (200) |
|---|---|---|---|
| Temperature index | 130 / 155 | 180 | 200 |
| Scratch and abrasion resistance | Good | Good | Very good |
| Chemical and refrigerant resistance | Moderate | Good | Very good |
| Cut-through temperature | Moderate | High | Highest |
| Relative cost | Lowest | Medium | Highest |
See our pages on polyester enamelled aluminium wire and class 180 polyesterimide wire for the single-coat options.
References and standards
- IEC 60317-25 – Polyester or polyesterimide overcoated with polyamide-imide enamelled round aluminium wire, class 200
- IEC 60317-0-3 – General requirements: enamelled round aluminium wire
- IEC 60851 series – Winding wires: test methods
- IEC 60085 – Electrical insulation: thermal evaluation and designation
Class 200 dual-coat aluminium (aluminum) winding wire: FAQs
What does the polyamide-imide overcoat add?
A hard, smooth, chemically resistant surface and a higher thermal rating. The overcoat raises scratch and cut-through resistance and lifts the insulation system to class 200.
Should I choose a polyester or polyesterimide base?
Polyester base gives slightly better adhesion and is more economical. Polyesterimide base is better for overload duty, long heat ageing and refrigerant environments.
Can class 200 aluminium wire be used in hermetic compressors?
Yes, if it is qualified with the refrigerant and oil used. Aluminium windings in compressors are generally designed to run at or below about 130 °C, well under the insulation's rating.
What diameters are available?
Typically 0.25 – 1.60 mm in grade 1 and up to 5.0 mm in grade 2, on spools or payoff drums.
How is quality verified?
Each lot is tested for dimensions, elongation, breakdown voltage, pinholes, heat shock and scratch resistance, and supplied with a test report.
Need class 200 aluminium winding wire?
Send base coat, diameter, grade, quantity and spool type. We will reply with test documentation and a delivered quote.
