Motors
Industrial and appliance motors that see high ambient temperatures, frequent starts or overloads: compressors, pumps, fans, washing machines.
Enamelled winding wire
Class 180 Polyesterimide Enamelled Round Aluminium Wire
Polyesterimide enamelled aluminium wire is a round annealed aluminium conductor insulated with a baked polyesterimide (PEI) film rated to thermal class 180 (class H). It handles higher winding temperatures and overloads than polyester wire, at a cost and weight well below copper. Metline supplies it to IEC 60317-15 and equivalent standards in grade 1 and grade 2 film builds, on spools sized for your winding lines, worldwide.
- Thermal class
- 180 °C (class H)
- Insulation
- Polyesterimide, single coat
- Diameter
- 0.25 – 5.0 mm
- Standard
- IEC 60317-15 / 60317-0-3
What polyesterimide enamelled aluminium wire is
Polyesterimide is a polyester resin modified with imide groups. The imide rings raise the softening temperature and thermal endurance of the film, which is why PEI is the standard insulation for class 180 winding wire.
The conductor is high-purity aluminium (typically 1350, 1370 or 1070-type) drawn to size and fully annealed so that it bends and winds without springback. The enamel is applied in many thin passes, each baked in an oven, until the specified film build is reached. Grade 1 is a thinner film for compact windings; grade 2 roughly doubles the film for higher breakdown voltage and better mechanical protection.
IEC 60317-15 covers this wire for grade 1 diameters from 0.400 to 1.600 mm and grade 2 from 0.400 to 5.000 mm, with general requirements for all enamelled round aluminium wire set out in IEC 60317-0-3. Finer sizes down to about 0.25 mm are produced to the same test methods by agreement.
Mechanical and electrical properties
The tables summarise key requirements for enamelled round aluminium wire. Values are indicative minimums drawn from the IEC 60317 aluminium parts; your purchase specification and its edition govern acceptance.
| 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 |
Breakdown voltages are room-temperature values measured by the twisted-pair or cylinder method of IEC 60851-5; requirements at elevated temperature are given in the standard.
Unidirectional scratch resistance
Scratch resistance measures how much force a loaded needle needs to break through the film to the conductor. It is the best single predictor of how well the wire will survive high-speed winding and slot insertion.
| Nominal diameter (mm) | Grade 1: mean (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 |
For intermediate diameters, use the value of the next larger listed diameter.
Sizes, film grades and packing
Supply range
- Conductor
- Annealed (O temper) electrical aluminium, about 61 % IACS
- Diameter
- 0.25 – 5.0 mm (grade 1 normally to 1.60 mm)
- Film build
- Grade 1 or grade 2; grade 3 by agreement
- Overcoat options
- Self-bonding (bondcoat) or polyamide-imide overcoat for class 200 – see our dual-coat page
- Spools
- Plastic or wooden spools (e.g. PT-series) from a few kg up to about 150 kg; cardboard drums for payoff-without-rotation
- Documents
- Test report per lot: dimensions, elongation, breakdown voltage, pinholes, heat shock, scratch
Application notes and limitations
- Hydrolysis: polyesterimide can degrade in sealed systems that trap moisture, so dry windings well before encapsulation and avoid water-containing hermetic systems.
- Chlorinated materials: avoid direct contact with PVC, neoprene and other chlorine-containing compounds, which release acids at temperature.
- Varnish compatibility: PEI is compatible with most polyester, epoxy and polyesterimide impregnating varnishes; confirm with a bond-strength or thermal-endurance test for new combinations.
- Terminating aluminium: aluminium's oxide film makes ordinary soldering difficult. Use crimp terminals designed for aluminium, resistance or ultrasonic welding, or specialised aluminium solders and fluxes; "solder-through" behaviour quoted for copper PEI wire should not be assumed.
- Sizing the conductor: aluminium's resistivity is about 1.64 times that of copper, so an equal-resistance winding needs about 1.28 times the diameter. Check slot fill before converting a copper design.
Where class 180 aluminium wire is used
Transformers
Dry-type and small power transformers, ballasts, and microwave-oven transformers where weight and cost matter.
Coils and actuators
Relays, solenoids, contactor coils and electromagnetic brakes.
Induction heating
Induction-cooker coils and other high-temperature coils where class 180 gives reliable margin.
Choosing between polyester, PEI and dual-coat wire
| Wire type | Thermal class | Typical use | Page |
|---|---|---|---|
| Polyester (PEW) | 130 / 155 | General motors, transformers, appliances | Polyester enamelled aluminium wire |
| Polyesterimide (EIW) | 180 | Hotter motors and transformers, overload duty | This page |
| Polyester or PEI + polyamide-imide overcoat (EI/AIW) | 200 | Hermetic compressors, heavy-duty motors, demanding winding | Dual-coat class 200 wire |
References and standards
- IEC 60317-15 – Polyesterimide enamelled round aluminium wire, class 180
- IEC 60317-0-3 – General requirements: enamelled round aluminium wire
- IEC 60851 series – Winding wires: test methods
- IEC 60172 – Test procedure for the determination of the temperature index of enamelled winding wires
Polyesterimide enamelled aluminium (aluminum) wire: FAQs
What does class 180 mean?
The insulation has a temperature index of at least 180, meaning it is expected to deliver about 20,000 hours of service at 180 °C in standard thermal-endurance testing. In practice windings are designed to run below that hot-spot limit.
What is the difference between grade 1 and grade 2?
Grade 2 has roughly twice the enamel thickness of grade 1. It gives higher breakdown voltage and better scratch resistance but takes more slot space. Grade 1 suits compact, low-voltage coils; grade 2 is standard for most motors and transformers.
Can polyesterimide aluminium wire be soldered directly?
Not like solderable copper wire. Aluminium's oxide layer prevents normal soldering, so terminations use crimps rated for aluminium, welding or special solders and fluxes.
Is aluminium winding wire as good as copper?
It conducts about 61 % as well by volume, so windings are larger, but they weigh about half as much for the same resistance and cost less. Many motors and distribution transformers use aluminium successfully where space allows.
What sizes and spools can you supply?
Typically 0.25 – 5.0 mm in grade 1 or 2, on plastic or wooden spools or payoff drums sized to your winding machines. Tell us your preferred spool type and net weight.
Need class 180 aluminium winding wire?
Send diameter, film grade, standard, quantity and spool type. We will reply with test documentation and a delivered quote.
