. The practical telephone handbook and guide to the telephonic exchange . Fig. 86 Scale Fig. 87 which the moving parts are magnetic in themselves, or aremaintained in a magnetic state by the induction of well-known Siemens relay is constructed on this prin-ciple, and a modification of it was adopted to form the polarisedbell. Figs. 86 and 87 represent a common form of the bell. Anelectro-magnet formed of bobbins, A and B (wound to aresistance of about 500 ohms each), is screwed to a soft-iron base, c, serving as its yoke. In the centre of c is screwedone pole, N, of a permanent mag
. The practical telephone handbook and guide to the telephonic exchange . Fig. 86 Scale Fig. 87 which the moving parts are magnetic in themselves, or aremaintained in a magnetic state by the induction of well-known Siemens relay is constructed on this prin-ciple, and a modification of it was adopted to form the polarisedbell. Figs. 86 and 87 represent a common form of the bell. Anelectro-magnet formed of bobbins, A and B (wound to aresistance of about 500 ohms each), is screwed to a soft-iron base, c, serving as its yoke. In the centre of c is screwedone pole, N, of a permanent magnet. At the ends of the basec two brass rods, e and f, are screwed, the prolongation ofthe screws serving to clamp the bell to the instrument case aand p are also furnished, at their opposite ends, with screws SUB-STATION APPARATUS 97 and nuts, with which the brass bar h is secured in position,and can be adjusted. In the centre line of h two pivot screwsare fixed, on which a soft-iron armature, J, can vibrate aboutits centre, just in front of the ends of the magnet
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelephone, bookyear19
