The inductor of a K-W magneto is shown in [Figure 46]. It consists of a shaft on which are mounted two blocks of iron at right angles. The section of shaft that joins them is the core of the winding; the wire is wound on it just as thread is wound on a spool, but with a space between, so that the shaft may revolve inside of the coil.
[Figure 47] shows the inductor in three positions of its revolution between the poles of the magnet. When it is in the first position, magnetism can flow from one pole of the magnet to the other by going into one end, A, of one block, through the core, and out of one end, C, of the other block. This makes a magnet of the core and it forms magnetism of its own. When the inductor turns to the second position magnetism can get across without flowing through the core, for the blocks now give it a path. As the flow through the core ceases, the core’s magnetism dies away, which gives the change in strength that is needed to produce a sparking current.
Fig. 47.—“K-W” Inductor in Three Positions
When the inductor is in the third position, the core again becomes the path for the magnetism and is magnetized; these changes continue as long as the inductor turns.
Fig. 48.—“Dixie” Inductor
While an armature type of magneto, like the Bosch, produces two sparks to every revolution, the K-W produces four, for there are four periods during every revolution when there is sufficient change in the strength of the magnetism of the core to produce a sparking current.
In these magnetos the revolving shaft is parallel to the ends of the magnets, but in the Dixie magneto it is at a right angle, as shown in [Figure 48]. The shaft is of some metal, such as brass or bronze, through which magnetism will not flow; otherwise the shaft would form a continuous path. The inductor blocks are mounted on the shaft, and act as extensions of the poles of the magnet. The core on which the wire is wound is a separate piece, placed under the arch of the magnets, with ends that extend down and form a tunnel in which the inductor revolves.
[Figure 49] shows an end view of the inductor, the magnets being cut away so that the core may be seen. As inductor block A is an extension of one pole of the magnet, magnetism tries to flow from it to block B, which is an extension of the other pole of the magnet. When the inductor is in position [1, Figure 49], magnetism can flow from block A through the core to block B, the core then being magnetized. In position 2, magnetism can flow from one block to the other by going through the ends of the core instead of through the core itself; the core then loses its magnetism, but regains it when the inductor moves to position 3.