Three compression-molded glass polyesters laminated into insulation sheets now have UL approval and a rating to 220ºC. The materials, HST-II, HTF, and H515, are intended for dry-type high-voltage transformer insulation and elsewhere. The insulations work well in applications that call for high thermal indices. The materials are said to deliver excellent retention of electrical and mechanical properties at elevated temperatures. All products are stable at their 220ºC thermal temperature rating.
The correct insulating material can significantly prolong the life of a transformer by protecting the unit against the big enemy of dry transformers: heat. Notably, the C-Class temperature rating of the three insulation materials give engineers an option of using less copper or aluminum conductor, thereby providing opportunity to reduce expensive winding conductor costs for manufacturers. Each product has performance characteristics for different applications. For example:
HAYSITE HST-II is said to be the benchmark for high temperature FRP materials. Having been granted the UL’s highest thermal recognition ever by any glass polyester laminate (U.L. File No. E81893) with a 220ºC/210ºC rating for 1/8-in. thick and heavier, and a 210ºC rating for thicknesses from 1/32 to 1/8 in.
Standard epoxy and wood-based insulation boards can become unstable at 220ºC. HST-II, however, exhibits excellent compression strength, stability, and retention of electrical and mechanical properties at this temperature.
Industrial applications for the asbestos-free HST-II include high voltage transformers, oil-field transformers, and dc motors, among others. The thick and rigid 10 mm HST-II sheet produces combs to wind copper in between the transformer ‘hair comb’ slots to guide across the unit. It is also widely used in busbar strip supports to conduct electricity in a distribution board.
A range of pultruded standard angles and profiles, and channels can be manufactured with the HSTII’s base resin while retaining its high-temperature properties. Pultruded HST-II helps keep costs down because custom lengths are available to eliminate scrap. Typical sizes include thicknesses of 1/8 to 3/8 in. in 4 by 8-ft. sheets, with the 64-in. long sheet optimal for low waste.
HAYSITE HTF and H515: These are intended for coil-former insulations due to their flexibility as thin sheets that can be rolled into a cylinder around the base material, thus letting end-users manufacture their own insulation tubes. Providing superior flexibility, the HTF and H515 exhibit excellent retention of electrical properties at elevated temperatures up to 220ºC without adverse affects to product strength and stability. Current standard specs include stocked tan sheets: 36 x 72 in. and 48 by 96 in., thickness from 1/32 to 1/16 in. (0.8 to 1.6 mm).
With versatile flexibility and high-temperature capability, the HTF and H515 are best used for coil former insulation, channels-to-steel-core insulation, and combs.
Haysite Reinforced Plastics
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