ELECTROTECHNICAL SHEET GLASS FABRIC LAMINATE
GRADE STEB (NEMA GRADE FR-4)
Hgw 2372.1
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| It is a laminar pressed material manufactured on the basis of glass fabric impregnated withepoxy binder; thickness 0,50-50 mm It is intended for the work in the open air in the conditions of normal relative humidity in transformer oil at vol-tage more than 1000 W and frequency of current 50 Hz as well as in the conditions of higher humidity at voltage up to 1000 W and freguency of current 50 Hz. It possesses high mechanical strengh at moderate temperatures, high stability of electricalproperties at elevated humidity, low flammability. |
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| Physical mechanical and electrical properties |
| Standards |
Material grade |
| OCT 12652-74 |
STEB |
| NEMA-LI 1-1989 |
FR - 4 |
| IEC 60893-3-2 |
EP-GC 202 |
Property |
Test
condition |
Unit |
Value |
Standard |
Achieved |
| Volume resistivity (to 8 mm) |
C 24 / 23 / 93 |
Ohm-m |
5-10 10 |
2,3-10 13 |
| Tangent of dielectrik loss angle at 1 MHZ, not more than |
D 24 / 23 |
- |
0,04 |
0,014 |
| Inuslation resistance, not less than |
D 24 / 23 |
- |
5-10 4 |
8-10 4 |
| Breakdown voltage parallel to lamination (one-minute), not less than |
M90/transformer oil |
kVeff |
35 |
>35 |
| Dielectric strength normal to layers (one minute examine test), not less than |
M90/transformer oil |
kVeff |
12,1 |
17 |
| Flammability (vertical burning test) |
A |
_ |
_ |
V 0 |
| Flammability (vorizontal burning test) |
A |
_ |
HB |
HB |
| Breaking stress at bending normal to layers, not less than |
A |
MPa |
350 |
370 |
| Breaking stress at elongation, not less than |
A |
MPa |
220 |
328 |
| Charpy impact strength parallel to laminations on notched samples,not less than |
A |
kJ / m2 |
50 |
50 |
| Long-term permissible temperature |
A |
° C |
from - 65 to + 155 |
| Density |
A |
kg / m3 |
1750-2050 |
1900 |
| Sheet thickness |
mm |
0,50 - 50 |
| Standard sheet sizes |
mm |
1220 x 1020 2440 x 1020 |
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| Notes: |
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| A - without preliminary treatment; C- preliminary treatment in damp condition; D- preliminary treatment in |
| distilled water; E- preliminary treatment at the elevated temperature. Figures next to letters denote: the fist - |
| treatment duration (hours); the second - treatment temperature ( 0 C) ; the third - air relative humudity (%). |
