GB1410008A - Electricallyinductive windings - Google Patents

Abstract

1410008 Electromagnets; conductor insulation; ignition coils BANKFIELD ELECTRICALS Ltd 19 Sept 1972 [1 Oct 1971] 45926/71 Headings H1P and HIT A solenoid switch comprises a plastic element 2 riveted to a ferromagnetic metal element 1 housing a winding 3 and a movable contact 4 retained by spring 18 on a shoulder of a plunger armature 5 to engage fixed contacts 6, 6a bolted to exterior terminals. A conductive partition 8 divides the interior into two chambers and is apertured for the armature, slotted for location with an inward projection of element 2, and drilled for a connection to one end of the winding. The solenoid is carried by a brass former 11 positively connected into the partition 8 and retained by resilient washer 12 connecting to element 1, and the winding comprises a coiled strip of aluminium foil coated on one side with uncured plastic, e.g. epoxy or phenolic resin. After winding the coil is cured by baking or current energizing the turns and is cooled to solidify into a continuous block; one end being connected over former 11, partition 8 to element 1. The other end is connected to a further terminal (not shown) over a lead passing through the guide plate with sleeve insulation and connected to the winding two turns below its surface by adhesive conductive foil (Fig. 4, not shown). Primary and secondary windings may similarly be wound separately or in bifilar manner, with insulating coatings therebetween. Heat resisting insulant may be interposed between turns, or the insulant may be a precured layer with a further uncured layer thereupon. The ends of the windings may respectively be brought out to terminals, and connected in common to conducting former. One winding may be of normal copper wire. The coil arrangement is applicable to dynamo field windings or to ignition coils, in which one winding may be of conventional copper wire, and may be wound in a desired configuration over a dummy pole before curing.