Ignition Devices for Gas and Petrol Motors; With an Introductory Chapter Treating Specially of Structural Details, Choice, and Management of Automobiles (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902. Excerpt: ... makes of coils these parts may be modified in form or in position, we have lettered these portions, and shall make use of the same lettering in the following illustrations to indicate the same parts, whatever may be the changes introduced, either in form or in position. The iron core a consists in a cylindrical bundle of annealed soft iron wire, the diameter of the core being usually about of its total length. It is essential to the good working of a coil that the iron should be exceedingly soft, so that it may quickly and fully take up the lines of force arising from the passage of an electric current, and as quickly return to its normal condition when the flow ceases. For this reason it is usual to "anneal" the bundle of soft iron wires constituting the core by bringing it to a bright red heat in a clear fire and allowing it to cool very gradually afterwards. The function of the core is to concentrate the lines of magnetic force set up by the primary current in its flow round the coils of the primary wire, b, into a small compact space, which is occupied by the second winding, c. It also serves in all those cases in which a " trembling" contact breaker, d d', is attached to the coil, to rapidly make and break contact between the battery (or other source of current) and the coils of the primary, which it does by virtue of acquiring magnetism while the current is on, and of losing its magnetism when the current is off. When the two ends of the primary circuit P P are connected to a battery or accumulator, the current flows along through the contact screw d to the contact spring supporting the hammer d' round the coils of the primary bbbb. In so doing the current magnetises the core a. This attracts the hammer d', and breaks contact between the spring and...