American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 370
. Such a relay is that shown in top view in Fig. 236. It is a polarized relay,wound for duplex working, pm is the permanent magnet, which magnetizes the ar-mature A of the relay in the same manner as does the permanent magnet of the re-ceiver relay. The tops of the two bobbins b b are shown. The…
Telegraph
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