Enamelled Rectangular Wire for Transformers
Enamelled wire, also called magnet wire or winding wire, is a copper or aluminium conductor coated with a thin insulating film that prevents short circuits between turns. This is the rectangular format for transformer windings: conductor thickness 0.8 to 5.6 mm, conductor width 2.00 to 16.00 mm, width to thickness ratio 1.4:1, in polyester, polyester imide and acetal grades.
Production scope and material data
| Conductor thickness (a) | 0.8 - 5.6 mm |
|---|---|
| Conductor width (b) | 2.00 - 16.00 mm |
| Width to thickness ratio | 1.4:1 |
| Conductor material | Copper or aluminium |
| Grades | 120 acetal, 130 polyester, 155 modified polyester, 180 polyester imide, 200 polyester imide / polyamide-imide |
| Standard | GB5584.2-2009 |
| Copper resistivity at 20 C | 0.017241 ohm mm2/m maximum |
| Aluminium resistivity at 20 C | 0.02801 ohm mm2/m maximum |
| Film build | Thin 0.06 - 0.11 mm, thick 0.12 - 0.17 mm |
| Bonded layer | 0.03 - 0.06 mm |
| Thermal class | F 155 C, H 180 C, C 220 C |
Problems this solves
- Film damage during winding that only shows up as a turn-to-turn short after impregnation
- Thermal class mismatched to the actual hot spot temperature, shortening insulation life
- Film build variation that throws out the calculated fill factor of the coil
- Specifications outside standard catalogue dimensions being refused
Why buyers pick it
- Thermal classes from F at 155 C and H at 180 C through to C at 220 C
- Film build selectable: thin 0.06 to 0.11 mm or thick 0.12 to 0.17 mm
- Copper and aluminium conductors, soft temper, to GB5584.2-2009
- Self-adhesive bonded grades with an adhesive layer of 0.03 to 0.06 mm
- Film thickness monitored in production with a dielectric loss meter
Technical detail
The insulation film provides electrical isolation and mechanical protection to the conductor. Thermal class sets the maximum continuous operating temperature the film survives without degrading, and voltage rating follows the application, with higher ratings needed for transformers in power distribution service. Conductors can be solid or stranded; stranded gives more flexibility where the winding needs frequent bending or movement.
Quality control
Enamel thickness is monitored during production with a dielectric loss meter rather than checked only at the end. Soft copper and soft aluminium rectangular conductors are verified against the resistivity limits in GB5584.2-2009 at 20 C.
Customisation
Film thickness outside the standard thin and thick bands can be manufactured to the specification you provide. If your conductor dimensions fall outside the 0.8 to 5.6 mm by 2.00 to 16.00 mm range, send them and they will be checked against the production scope before quoting.
How it compares
Against foil, enamelled rectangular wire lets you build a defined number of turns with a calculated cross section and no interlayer paper, which suits high voltage windings. Foil is faster to wind and gives a full-width turn, which suits low voltage coils.
Who it is for
Transformer and reactor winding shops, motor and electromagnetic component makers, and engineers specifying magnet wire against a defined thermal class.
The material as it ships
Questions buyers ask about this item
What conductor sizes are available?
Thickness 0.8 to 5.6 mm and width 2.00 to 16.00 mm, with a width to thickness ratio of 1.4:1. Sizes beyond that range are checked against the production scope on request.
Which thermal classes do you supply?
Grades covering class F at 155 C, class H at 180 C and class C at 220 C, plus 120 acetal and 130 polyester grades.
Copper or aluminium conductor?
Both. Copper resistivity is held at 0.017241 ohm mm2/m or below at 20 C, aluminium at 0.02801 ohm mm2/m or below.
What film thicknesses can I order?
Thin film from 0.06 to 0.11 mm, thick film from 0.12 to 0.17 mm, or a build to your own specification.
Do you supply bonded self-adhesive wire?
Yes. The self-adhesive layer is generally 0.03 to 0.06 mm thick.
How is enamel thickness verified?
It is monitored in production with a dielectric loss meter.
What standard applies?
Soft copper and soft aluminium rectangular conductors comply with GB5584.2-2009.
Related material
Aluminium Foil for Transformer Windings
Thickness: 0.2 - 3.00 mm · Width: 20 - 1500 mm
View specification →
Copper Foil for Transformer Windings
Thickness: 0.2 - 3.0 mm · Width: 50 - 1350 mm
View specification →
Copper Strip for Transformer Windings
Thickness: 0.2 - 3.0 mm · Width: 50 - 1350 mm
View specification →Further reading
Ready to price this against your drawing?
Code or alloy, inner diameter, thickness, width and weight is all the sales desk needs to quote.