Variable speed electric motor - has movable permeable yoke bridging air gap between permanent stator magnets to alter flux

摘要

The variable speed motor has a mechanism in the permanently magnetic stator assembly to alter the air gap in the stator circuit and thereby alter the flux which consequently changes the speed. The halves of the stator circuit (3, 4) are separated from one another by two air gaps. A yoke (6) bridges one of these air gaps and its motion alters the flux in the stator circuit. The bridge is driven radially towards, and away from, the gap by a lever mechanism, or it may slide in and out of the gap. The highest rotational force is delivered at small revolutions which is advantageous in e.g. dough mixers and hand drills.