Two Master Clocks and Distribution Board removed from (old) Scotland Yard before they turn it into a hotel.

I bought this from auction, it’s such an interesting combination, the C7’s have been modified to include a second-hand movement, both Master Clocks should be wired to the Distribution Board and must have ran clocks across 21 floors in Old Scotland Yard. So if we estimate 3 clocks per for that would mean that this setup services 63 slave dials. It’s a shame that the slave clocks where not part of the auction lot. Gents’ of Leicester slave clocks with a second-hand are pretty rare right?

There is a service log that accompanied the lot, dating from 1965 to 1972. Although the logs by the service men are not in an official Gents’ logbook, but rather on a single piece of paper with the Royal Coat of Arms of the United Kingdom to the top corner, I assume it was just some paper that was lying around Scotland Yard that the Service men used to log the services of the clocks. That made me think did Gents’ of Leicester even branded logbooks made for large establishments like Scotland Yard, or even to keep a service record of any clock? Has anyone come across a Gents’ logbook?

I assume that something like this setup, was made to order, adding the custom second-hand movement and extra transistor added on the Gents’ production line.

If anyone can shed some more light on the details of this fascinating piece of equipment, please feel free to comment below. The below information is predominantly comments by a friend who is very knowledgeable in this area and used to service Gents’ equipment, so a huge thanks to him for helping me get these up and running. 

There are two accommodating Master Clocks, both which wire into the Distribution Board. Modified to include a second-hand function.

SLAVE DIALS

Looking at the loop output terminal strip at the bottom, it controls 10 loops possibly high current via the top hat transistors which would suggest quite a few slaves on each loop. All of the slave dials would be synchronised and monitor each output.

WORKING CURRENT

The working current is still 0.22 ohms per loop and the transistors would protect the mechanical contacts from excess arking if a high number of slaves are employed, the voltage would be quite high. The rheostats do the same job as the C7, set the current in the loop. The 3 position switches are self explained, advance, retard and normal or run.

Can anyone shed some information on why there is a 1 minute slave (bottom left from back) and where it gets its 60 second pulse from (possibly the other C7)?

The distribution panel is a interesting device, I’ve not seen many of these around, perhaps a purpose built piece of kit made specifically for (old) Scotland Yard on request.

SLAVE DIALS

Inside in the front panel there are 12 slave movements.

MERCURY TILT SWITCHES

The movement at the top right is a timing cam for the Mercury tilt switches, they are energised by the GPO type relays that engage when the cam contacts close, they will tilt and the Mercury will flow through the tube shorting a pair of contacts for the duration of the flow, normally 6 seconds and ring a bell or any other output device. The Mercury will flow back after the next 30 second pulse and releasing the GPO relays.