Glass Yard
Due to technological advances in the electromechanical industry during the last decades, there was a need to introduce new insulating systems which would provide higher coefficients of safety as regards thermal aging current electrical machines undergo.
At the same time, the ongoing and constant development of insulating materials led to a new insulating method based on glass yarn.
Around 1934, Corning Glass Works and Owens Illinois Company started producing filaments which could be used in the textile industry, which oriented their products (threads, tapes and fabrics) to the insulation of electrical equipment.
Composition and Properties
Glass used in this area has a special composition, called E-type glass. In this composition we can find an almost complete lack of alkali, which ensures that if it does not have soluble salts will reduce hygroscopicity, the superficial conductivity (there is no hydrolysis in surface) increase resistance to water and to alkali; and decreases resistance to acids.
Electrical Properties: (average)
| Dielectric constant | 6.3 |
| Power factor | 0.0015 |
| Dielectric strength | 90kv/mm |
Physicochemical Properties
– High temperature resistant.
– High tensile strength.
– Fireproof
– Nonflammable.
– High chemical resistance.
– Oil resistant.
As can be seen from the above properties, we have a material which can fit in many insulating systems according to the way it is used. We will start from the simplest way: yarn fabrics and tapes without coating.
Fabrics
| Thickness (mm) | Width (cm) | Weight (gr/m2) | Load/break (kg/cm) |
| 0.035 | 100 | 30-32 | 10 |
| 0.06 | 100 | 60 | 12 |
| 0.08 | 100 | 100 | 20 |
| 0.10 | 100 | 113 | 22 |
| 0.12 | 100 | 113 | 22 |
| 0.18 | 100 | 160 | 29 |
| 0.28 | 100 | 300-305 | 37 |
| 0.40 | 100 | 410 | 78 |
Fibreglass tape without varnishing
| Thickness (mm) | Width (mm | Load/break (kg/cm) |
| 0.08 | 10 | 21 |
| 0.08 | 15 | 31 |
| 0.08 | 20 | 42 |
| 0.12 | 10 | 26 |
| 0.12 | 15 | 40 |
| 0.12 | 20 | 52 |
| 0.12 | 25 | 67 |
| 0.18 | 10 | 38 |
| 0.18 | 15 | 56 |
| 0.18 | 20 | 76 |
| 0.18 | 25 | 92 |
| 0.18 | 30 | 112 |
| 0.25 | 10 | 41 |
| 0.25 | 15 | 63 |
| 0.25 | 20 | 82 |
| 0.25 | 25 | 103 |
| 0.25 | 30 | 126 |
Also, there are other extremely useful and important elements such as braided lining and cords. All the properties mentioned indicate that glass yarn tapes and fabrics are important elements in supporting other substances with well-known insulating characteristics (silicones, elastomers, resins, epoxies, mica, etc.)
Coils with fibreglass tape
Polyester Tape
It is a tape made of polyester yarns in the weft and chain, 0.15 – 0.17mm thickness. It is manufactured in widths of 15, 20, 25, and 30mm.
Unit: 50 m long rolls.
Cotton tape
It is a tape woven with cotton yarns in the weft and chain, 0.13 – 0.20mm thickness. It is manufactured in widths of 10, 20, 25, and 30mm.
Units: 100 m long rolls.
Triaxial Cord Code 270
To perform different types of fastening on coil heads and any other sector that for some reason needs to fix elements of the winding.
It has more flexibility than covered cords and allows to make knots in a simpler way. The glass wick has a treatment (finish), compatible with varnishes and resin epoxies that ensures a greater fixation.
Units: 100mts long rolls.
Thickness: 3mm.