Slot wedges are used as closures for the slot in the electro machine and generator construction.
Glass fibre reinforced materials are mainly used for the manufacture of slot wedges.
The slot wedges can be manufactured of plate materials. In this case resin systems of polyester, epoxy or polyimide are used. Glass fibre is almost the exclusive reinforcing material. The outline of the slot wedges is milled out of the full.
Slot wedges are manufactured with pultrusion. This means that glass fibres are drawn through a resin bath (polyester- or epoxy resin) and then they cure in the tool. The tool defines the outline of the slot wedge.
Another manufacture technology for slot wedges is to press the outline of the material in a tool made of prepreg. With this technology special mechanical values are met.
In the past slot wedges made of beech wood were used. Wedges made of beech wood are found rarely, although they have the advantage of expanding which leads to slot fixing.