Nanocrystalline cores compliant with the EN 45545 fire safety standard

EN 45545 is a mandatory European fire safety standard for all materials used in the construction of railway vehicles. It protects passengers and staff by stopping fires from starting, slowing the spread of flames, and limiting dangerous smoke and toxic gases

The standard applies to all trains, trams, and subways in Europe.

To meet EN45545 thermal class requirements for our transformer cores, we have developed a targeted technical solution during the manufacturing of nanocrystalline cores.

1. PPS material is used for core encapsulation to ensure the entire core assembly achieves Class H thermal rating. Note that PPS tooling costs are relatively high.

2. During the prototyping phase, to mitigate PPS tooling expenses, we implemented an alternative approach involving impregnation of nanocrystalline cores with glass tape reinforcement to achieve equivalent Class H thermal performance. The detailed process flow is as follows:

   - First, annealed nanocrystalline cores are impregnated with Class H-rated epoxy resin and cured.

   - Second, the cores are wrapped with one layer of fiberglass tape for enhanced insulation.

   - Finally, wrap one layer of fiberglass tape first, then impregnate and cure. Subsequently, wrap one additional layer of Teflon (PTFE film).