Selco Co., Ltd., for High-Density and Special Coils

* By compression molding, the coil is packed to fill the core space.

achieve a fill factor of 89-93% without damaging the coating of round wire!

Filling the core space completely through compression and molding

Data comparison before and after compression and molding

(Coil using self-fused wire with diameter of 0.9 mm)

Layer short circuit testing after compression　800V 1500V

10-pulse application　OK

Measurements taken using 3D measuring instrument, digital calipers,

Characteristic DCR meter, LCR meter, layer short-circuit tester (impulse application test)

Evaluated with withstand voltage tester

Image of the coil attached to the core

* The core needs to be a split core (upper diagram), or have strait teeth.

Explanation:

Coil is tightly wound in steps, then compressed and molded → 79-82% → 89-93%

(1) The process involves compressing and molding simultaneously with an air core coil wound to high density.

(2) Compressing the coil reduces the gaps between the coil wires.

(When protecting the coating is a priority, weakening the compression retains more thickness in the coating)

(3) Molding the coil flattens out the bumps in the stepped surface of the coil.

(4) The coil is inserted into straight teeth or a split core, but some kind of insulation is needed between the ground plane and the inner diameter of the coil and adjacent coil.

As a result, if the gap in the insulation between the inside of the coil or the core teeth is eliminated, gaps will be almost completely eliminated, increasing the fill factor beyond a flat wire stepped winding coil.