Transformers & Power Supplies
Transformer and power-supply manufacturing is the most specification-driven tape application in our range. Layer insulation, end-turn insulation, core strapping and lead dressing each call for a different construction, and the wrong choice shows up as dielectric failure or audible noise.
The dominant requirements are dielectric strength, class temperature and mechanical toughness.
What this application demands
Dielectric strength
Layer insulation sits between turns at full working voltage; breakdown voltage must be specified and verified.
Temperature class
Class F and class H designs need tapes that survive continuous operation at 155 °C and 180 °C respectively.
Mechanical toughness
Core strapping and lead dressing tapes must resist tearing during assembly and in service.
Conformability vs. stiffness
End-turn insulation often needs a tape that follows a curved surface but still holds its shape.
Recommended constructions
| Requirement | Recommended tape | Why |
|---|---|---|
| Layer and end-turn insulation | C8020 acetate cloth tape | High dielectric strength with moisture and mildew resistance; follows curved surfaces and stays in place. |
| Class H / high-temperature insulation | PI5300 polyimide tape or PT5200 PET high-temperature tape | Polyimide for the most demanding class H work; PET film to 180 °C where cost matters. |
| Core strapping and heavy bundling | BX8150W / BX8150H filament tape | Woven glass-fibre reinforcement gives very high tensile strength — the tape holds where cloth tape would tear. |
| Lead dressing and coil finishing | P105Z PVC film tape, or B1300 PET cloth tape | PVC for flexible, low-cost finishing; PET cloth where abrasion protection is also needed. |
How to specify it
| Specification point | What to state on your enquiry |
|---|---|
| Insulation class | Class B, F or H, with the winding temperature rise |
| Dielectric requirement | Breakdown voltage and the layer thickness it must be achieved in |
| Operating temperature | Continuous and short-term, including any varnish or curing oven exposure |
| Mechanical duty | Whether the tape is purely insulating or also structural |
Common specification mistakes
Watch out for this: reusing a harness tape
Abrasion-resistant harness tapes are not formulated for layer insulation; the dielectric requirement is different.
Watch out for this: under-specifying class H
Polyimide exists precisely because cheaper films cannot hold class H temperatures for a full service life.
Watch out for this: ignoring varnish compatibility
Impregnation varnish can attack some adhesives — tell us if the taped part is varnished.
Talk to a tape engineer
Send us the application, the operating temperature and the base material you have in mind. We will come back with a recommended construction, a datasheet and a quotation within one working day.