1.Electrical laminated wood is widely used as insulating and supporting material in transformers and instrument transformers. It has many virtues such as moderate specific gravity, high mechanical properties, easy vacuum drying, easy mechanical processing etc. The dielectric constant of this material is close to transformer oil, so it makes a reasonable insulation match. And it can be used in transformer oil of 105℃ for long time.
2.People usually use this material to make upper/lower pressure pieces, cable supporting beams, limbs, spacer blocks in oil-immersed transformers, and clamps in instrument transformers. It replaced steel plates, insulating paper sheets, epoxy paper sheets, epoxide woven glass fabric lamination in these fields, and cut down the material expenses and weight of transformers.
3.The raw materials of electrical laminated wood are high quality birch and willow timbers. After boiling, rotary cutting, drying, these timbers are made to veneers. At last the veneers will be glued with special insulating gluewater and processed under high temperature and pressure.
Veneer Max Specification: (length × width ×thickness)： 4000×3000×120（mm）
1、Boards Flatness（mm）
|
|
Distance of points on the veneer face from light weight straight ruler |
|
Normal Thickness |
500 straight ruler |
1000 straight ruler |
|
≤15 |
2 |
4 |
|
＞15…≤25 |
1.5 |
3 |
|
＞25…≤60 |
1 |
2 |
|
＞60 |
1 |
1 |
2、Surface Quality
|
Item |
Allowed Range |
|
Swelling |
Not Allowed |
|
Cracking |
|
Dead knot |
|
Foreign-body adhering |
|
Insect hole |
|
Rot |
|
Contamination |
|
Bruising |
A few allowed，not effect in usage |
|
Impression |
|
Color-odds and splash |
|
Patches per sq.m. on surface |
≤3 | 3、Electrical Laminated Wood Technique Target Table
|
Capability |
Unit |
Model |
|
|
Technique target |
Rings technique target |
|
|
B1 |
B2 |
B3 |
B4 |
B5 |
B6 |
B7 |
|
|
Appearance density |
g/cm3 |
1.1~1.2 |
0.7~0.9 |
0.9~1.1 |
1.1~1.2 |
1.2~1.3 |
0.9~1.1 |
1.2~1.3 |
|
|
Moisture |
% |
≤6 |
≤6 |
≤6 |
≤6 |
≤6 |
≤6 |
≤6 |
|
|
Vertical layer direction flexural strength |
Direction A |
MPa |
≥150 |
≥45 |
≥55 |
≥65 |
≥80 |
Diameter＞1000mm |
≥100 |
≥140 |
|
|
|
|
Direction B |
Diameter≤1000mm |
≥90 |
≥125 |
|
|
|
Vertical layer directionmodulus of elasticity |
Direction A |
GPa |
≥14 |
≥4.5 |
≥6 |
≥8 |
≥9 |
≥10 |
≥13 |
|
|
Direction B |
|
|
|
Compressibility |
|
% |
≤3 |
≤5 |
≤4 |
≤3 |
≤2.5 |
≤5 |
≤4 |
|
|
（Below 20MPa） |
|
≥70 |
≥70 |
≥70 |
≥70 |
≥70 |
≥70 |
≥70 |
|
|
Impact strength |
Direction A |
KJ/m2 |
≥35 |
≥6 |
≥10 |
≥13 |
≥15 |
≥25 |
≥35 |
|
|
（side test） |
Direction B |
|
|
|
Shear strength |
MPa |
≥8 |
≥5 |
≥7 |
≥8 |
≥9 |
≥7 |
≥9 |
|
|
Vertical layer direction |
KV/mm |
≥11 |
≥9 |
≥10 |
≥11 |
≥12 |
≥10 |
≥10 |
|
|
Electric trength |
|
|
In （90±2）℃ Oil |
|
|
Parallel layer direction |
KV |
≥50 |
≥50 |
≥50 |
≥50 |
≥50 |
≥50 |
≥50 |
|
|
Electric trength |
|
|
In （90±2）℃ Oil |
|
|
Shrinkage after dried |
Direction A |
% |
≤0.2 |
≤0.3 |
≤0.3 |
≤0.3 |
≤0.3 |
Girth |
≤0.5 |
≤0.5 |
|
|
Direction A |
≤0.5 |
≤0.3 |
≤0.3 |
≤0.3 |
≤0.3 |
|
|
Thickness |
≤3 |
≤3 |
≤3 |
≤3 |
≤3 |
|
|
|
|
|
Oil absorption |
% |
≥8 |
≥20 |
≥15 |
≥8 |
≥5 |
≥10 |
≥5 |
|
|
Contamination to liquid dielectric |
— |
≤0.1 |
≤0.1 |
≤0.1 |
≤0.1 |
≤0.1 |
≤0.1 |
≤0.1 |
|
|
（Δtanδ） |
|
|
4:Nominal thickness and allow the permissible variations (unit mm) |
|
Nominal thickness |
Allow deviation |
|
≤10 |
±1.4 |
|
＞10-≤15 |
±1.6 |
|
＞15-≤20 |
±1.8 |
|
＞20-≤25 |
±2.0 |
|
＞25-≤30 |
±2.2 |
|
＞30-≤40 |
±2.6 |
|
＞40-≤60 |
±3.0 |
|
＞60-≤100 |
±4.0 |
|
＞100-≤150 |
±4.0 |
|
5：Plank nominal length and width and allow deviation (unit mm) |
|
Length and width |
Allow deviation |
|
＞100-≤250 |
±0.8 |
|
＞250-≤500 |
±1.0 |
|
＞500-≤1000 |
±2.0 |
|
＞1000-≤2000 |
±3.0 |
|
＞2000 |
±4.0 |
5、Packing:Packaged in wooden crates,wooden framed cases or other strong enough materials covered with moisture-proof material outside.Gross weight of each packaged not exceeds 3000kgs.
6、Storage:Products should be stored in a clean and dry room with temperature not exceeding 40℃ and should be laid flat wise on a stepping-board which is at least 50mm from the ground, not close to fire,heat source and protected against moisture.
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