Transformer Insulation Materials
Pultruded Fiberglass Stays
Dog-bone profile stays in pultruded alkali-free fiberglass, Class F
Alkali-free fiberglass impregnated with thermosetting resin and pultruded into a dog-bone profile, for coil stays and turn/slot insulation in Class F and H motors and in oil-immersed transformers.
Class F (155°C)Density 1.8–1.9 g/cm³PTI ≥600 V
- Temperature class
- Class F (155°C)
- Material
- Alkali-free fiberglass + thermosetting resin
- Standard length
- 1000 mm
- Profile
- Dog bone
Request a quotation or a sample. Tell us thickness, width, temperature class, quantity and delivery form. We reply within one business day.
Technical data
| Property | Unit | Value |
|---|---|---|
| Material | — | Alkali-free fiberglass + thermosetting resin |
| Density | g/cm³ | 1.8–1.9 |
| Impact strength | kJ/m² | ≥90 |
| Heat distortion temperature (Method A) | °C | ≥240 |
| Bending strength | MPa | ≥200 |
| Compression strength (axial) | MPa | ≥200 |
| Insulation resistance, normal | Ω | ≥1.0×10¹² |
| Insulation resistance after 24 h water immersion | Ω | ≥1.0×10¹¹ |
| Electric strength, 90°C transformer oil | kV/mm | ≥10 |
| Arc resistance | s | ≥180 |
| PTI index | V | ≥600 |
| Flammability | — | FV0 |
| Temperature class | — | Class F (155°C) |
Values are typical values or ranges from our product data. Bulk supply is subject to the approved specification, sample and test report. If a parameter you need is not listed here, ask our engineers for the full test report for that grade.
| Profile | Profiles available (mm) |
|---|---|
| Dog bone group 1 | 6×6, 6×7, 6×8, 6×10 |
| Dog bone group 2 | 8×8, 8×10, 8×12, 8×13, 8×15, 8×20 |
| Dog bone group 3 | 10×10, 10×11, 10×12, 10×14, 10×15, 10×16 |
| Dog bone group 4 | 12×12, 12×14, 12×16, 12×20, 12×24 |
| Dog bone group 5 | 14×14, 14×16, 14×18, 14×20, 14×24 |
| Dog bone group 6 | 16×16, 16×18, 16×20, 16×22 |
Key features
- Pultrusion gives a stable cross-section and controlled fiber orientation.
- The dog-bone profile locates securely and reduces coil-stay loosening.
- Oil, moisture and flame resistant for Class F/H motors and oil-immersed applications.
Applications
Slot, turn and end stays in Class F/H motors and generators; coil stays in oil-immersed transformers.
Electric Motors & GeneratorsOil-Immersed TransformersReactors
Why it fits
A structural insulation part that keeps its dimensions after impregnation and curing - so the coil stays tight.
Ordering information
To receive a quotation, please confirm:
- Product and grade
- Thickness and width (and roll or sheet size)
- Temperature class
- Quantity and delivery form (roll / sheet / die-cut / machined)
- Destination port and required delivery date
For machined parts, attach a drawing in PDF, DWG or STEP format. Datasheets, COAs and batch test data are available on request.
Related materials
Often specified together
Send your specification
Our export team reviews the application, the process and the existing specification before recommending a construction.