Introduction
Insulation class: A (105 °C)
100% sulphate wood pulp
Natural-color
Precompressed pressboard, even fiber orientation, hard and dimensionally stable
High purity and mechanical strength
Low shrinkage, fiber-free surface
Good compatibility with liquid dielectrics
Duct strip is made from high quality pressboard G4 grade. It has excellent transformer oil impregnation feature, high compressive strength more than corrugated pressboard which is the old technology. It is used at high temperature condition and it could be improved the circuit strength.The character are below:
1. High mechanic strength
2. High electric strength
3. Accurate dimension
Application: Oil duct strip provides duct for the flow of the cooling oil in layer and strip windings in distribution power transformers. It is manufactured by bonding transformer board sticks onto insulating paper or single-coated diamond dotted paper.
Main strips: Rectangular strips, T-strips, Pigeon cauda strips, Abnormity strips.
PRESSBOARD STICK 4*5*1000MM| ITEM | TYPICAL VALUES | MATTER OF FACT |
| Thickness: mm | 4mm±7.5% | 4.1-4.3mm≤7.5% |
| Width | 5±0.5mm | 4.95-5.38mm≤0.4mm |
| Length of 1000mm: | ±5mm | 1000±3 mm |
| Pitch of stick centre: | ±3mm | 23±2 mm |
| Apparent density: g/cm3 | 1.1-1.2 | 1.18 |
| Moisture content ,% | 4.0 to 9.0% | 5.7 |
| PH water extract: | 6.0 to 9.0 | 6.8 |
| Ash content,% maximum | 1% | 0.51 |
Tensile strength Mpa
Machine direction:
Cross machine direction: |
≥90
≥50 |
107.4
101.3 |
| Oil absorption | ≥7.0% | 12.29 |
Shrinkage rate% MD
CMD
Thickness D | ≤1.0
≤1.4
≤6.0 | 0.16
0.25
≤5 |
Elongation rate MD
CMD | ≥3
≥4 | ≥4.4
≥4.4 |
| Conductivity of aqueous extract Ms/m | ≤10.0 | 5.03 |
Dielectric breakdown:(Kv/mm )In Air
In Oil | 10
24 | 16.7
35.7 |
