The trafo must be wrapped by a metal clamp and both the clamp and the silicon iron plates are enamelled to reduce the Foucalt currents and the unwanted heating of the trafo.
If the required or available spool has a geometric section larger than that calculated, you can place more stacked sheets (increasing B) so that the core is firmly attached to the spool, but always use the smallest possible spool. One winding should be separated from the other with a self-contained cardboard that is sold in homes that work with materials for transformers.
To assemble the transformer we first wind the primary winding and then the secondary winding (or secondary windings), where each winding must be insulated by cardboard, even the different secondary windings. We can fasten the cardboard with varnish and after the windings are finished, we must put a sheet of cardboard.
The material needed to wind a trafo is:
– enameled copper wire usually sold per kilo or reel;
– silicon iron core, sold per kilo;
– cardboard, normally sold per sheet;