The LPIEC of the coaxial configuration contains a fixed inductor
with a two-layer winding of the disk shape, which is wound with a rectangular copper busbar, is epoxy resin and is laid either in a thick-walled insulating (fiberglass) or in a thin-walled (1 mm) steel frame  (Fig.
A fixed inductor
has no magnetic core, or has a core whose air gap and position within the coils are fixed.
The E320 VAR-04 clutches require no wear adjustment and feature sealed bearings for dry operation and a fixed inductor
mounted on the ball bearings.
The experimental results show that the model is both suitable for the fixed inductor
and the gradually changed inductor.