BELL No. 25A
A bell of 1 ohm resistance. It operates with a D.C. voltage with the polarity reversed 7 time per second (3.5hz).
Uses two Bell-gong No. 8.
The components are mounted on a mahogany stand and terminals are of the thumbscrew type. The stand is 12" high by 10" across by 4½" deep.
The bell mechanism has four, 0.25 ohm, windings in series giving a total resistance of 1 ohm for the four coils.
Used in the UK House of Commons as a Division bell in conjunction with a Transmitter, Division Bell (Drawing No. 1378). As from 1913, bells used external to the Parliamentary estate were standard A.C. bells working at 25hz.
This bell produced a sedate, lazy, ring unlike normal telephone bells and were fitted in ornate wooden enclosures.
Probably introduced around 1904.
Drawing - 90013.
Specification - S3A.
Last revised: July 11, 2023