The telephone system of the British post office. A practical handbook (1901)
Herbert, Thomas Ernest · London, New York, Whittaker and Co. · leaf 61
ly arelatively small central bar, around which a large number of turns of wireare wound. This is the shape of the armature in section. It is usuallyabout an inch in diameter and from three to four inches long, and iswound with silk-covered copper wire of about 40 S.W.G.—i.e., 0048 inchin diameter.… … Figure 36. lines of force passing through the central or cross portion of the H—i.e.,there is the minimum number of lines through the conductors. Imaginenow that the armature is revolved until the curved ends of the armatureare precisely opposite the two pole pieces, as shown in Figure 36. Thelines…
Telephone · Postal service
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