Industrial equipment - Everett Edgcumbe “Synclock” Time / Frequency Difference Meter - United Kingdom - Synclock Difference Meter

Everett Edgcumbe “Synclock” Time / Frequency Difference Meter Circa 1935–1950 (most likely 1938–1948)
A rare and highly specialised industrial instrument manufactured by Everett Edgcumbe & Co. Ltd, London – one of Britain’s foremost makers of precision electrical measuring equipment in the pre- and immediate post-war period.
This is a Time/Frequency Deviation Indicator used in electricity generating stations, substations, large industrial plants and railway signalling installations. It continuously displays the cumulative difference between a high-accuracy “Standard Time” reference (quartz master clock or radio time signal) and the time derived from the 50 Hz mains frequency.
Engineers monitored the separation between the black minute/second hand and the red index hand to keep the grid frequency within very tight limits, ensuring that millions of synchronous electric clocks across the country remained accurate.
Key features - Enamel dial with the characteristic “STANDARD TIME” and “MEAN FREQUENCY IS NORMAL / ABOVE NORMAL” legends - Clearly labelled Everett Edgcumbe “SYNCLOCK MOTOR” - Heavy black-painted steel bulkhead case with hinged bevelled-glass bezel - Dual motor switching (“MOTOR No.1 / No.2 / OFF”) for redundancy - Marked “110 V D.C. 0.2 A” – this is a scarce DC-powered variant
Condition is complete, original and undamaged with honest industrial patina and light surface corrosion typical of genuine power-station use.
No cracks to the dial, glass intact, hands and mechanism excellent.
Electrically untested but visually superb for display or straightforward restoration. Believe period to be 1935–1950, with this exact combination of dial layout, DC rating and case style placing it firmly in the late 1930s to immediate post-war years.
As-is, and untested.