| ELECTROTECHNICAL SHEET GLASS FABRIC LAMINATE GRADE ST-ETF (NEMA GRADE G11) Hgw 2372.4 |
| 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 | kVeff | 35 | >35 |
| Dielectric strength normal to layers (one minute examining test), not less than | 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 |
| 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 |
| Notes: |
| 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 (%). |
