Transmitter, Division Bell


This Transmitter is a device that is used to control the Division Bells at the UK Houses of Parliament.  These bells are rung for 30 seconds and this then allows Members of Parliament eight minutes to get to the voting booths.  Operated by a low D.C. voltage, which reversed polarity 7 times a second (3.5hz) this rang bells around the Parliamentary estate.  The system was extended to ring bells in residencies, hotels and bars in the Westminster area.  In 1913 the bells outside of the Parliamentary estate where changed to operate off a ringer, probably due to the distances and numbers involved and these were standard 25hz bells.

Introduced around 1904 at the same time as the Bell No. 25A

The device has four terminals, with C and Z connected to a battery and the other two the output, which connects to the division bells.

Totally mechanical in operation this device is started by pushing the rod down. The lead weight, which is connected to a chain, is drawn upwards by a rotating wheel which also has a ratchet attached.  On release of the plunger the wheel returns to it's normal position by means of the weight and a governor to control the speed.  During this time two electrical contacts, operated by the ratchet, reverse the polarity to the output 7 times per second over a period of 30 seconds.  This contact set can be seen in the centre of the picture below.  The contacts are normally covered by a glass plate.

The whole unit is 18" high by 9" across by 5" deep.

Diagram No's 1378 and 1379.

 

Original 1904 Transmitter

 

Later variant - date unknown

 

 

 
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Last revised: July 17, 2021

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