ELECTROTECHNICAL SHEET GLASS FABRIC LAMINATE
GRADE ST-ETF (NEMA GRADE G11)
Hgw 2372.4
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It is a laminar pressed material manufactured on the basis o glass fabric impregnated withepoxy polifunctional binder ; thickness 0,35-50 mm It is intended for the work in the conditions of normal relative humidity and in transformer oil at voltage more than 1000 W and frequency of current 50 Hz as well as in the conditions of elevated 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, high thermal stability. |
Physical mechanical and electrical properties |
Standards |
Material grade |
OCT 12652-74 |
ST-ETF |
NEMA-LI 1-1989 |
G-11 |
IEC 60893-3-2 |
EP-GC 203 |
Property |
Test condition |
Unit |
Value |
Standard |
Achieved |
Volume resistivity (to 8 mm) |
24 / 23 / 93 |
Ohm-m |
1-10 10 |
7,0-10 12 |
Tangent of dielectrik loss angle at 1 MHZ, not more than |
24 / 23 |
- |
0,04 |
0,012 |
Inuslation resistance, not less than |
24 / 23 |
- |
5-10 4 |
1,2-10 6 |
Breakdown voltage parallel to lamination (one-minute examining test), not less than |
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kVeff |
35 |
>35 |
Dielectric strength normal to layers (one minute examining test), not less than |
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kVeff |
13,1 |
17 |
Splitting effort, not less than |
A |
H |
2500 |
4600 |
Breaking stress at bending normal to layers, not less than |
A |
MPa |
350 |
460 |
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MPa |
- |
310 |
Breaking stress at elongation, not less than |
A |
MPa |
220 |
340 |
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 + 180 |
Density |
A |
kg / m3 |
1700-1900 |
1890 |
Sheet thickness |
mm |
0,35 - 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 damp treatment; D- preliminary treatment in distilled water |
E- preliminary treatment at the elevated temperature. Figures next to letters denote: the fist - treatment |
duration (hour); the second - treatment temperature ( 0 C) ; the third - relative humudity of air (%). |