Western Union self-winding clock

It might also be a conventional mechanical clock, normally spring-driven, with a soldenoid and switch to wind it when the spring runs down (smaller clocks of this type were fitted to UK cars in the 1960s, I've had a few across my bench. They used a tension spring (not a flat spiral spring like most mainsprings) and rewound every couple of minutes or so). If it is a syncronome, there are likely to be contacts for slave dials too That book is moderately hard to find (I have) it, there's also 'Electric Clocks' by the same author that I've not found yet. Other books including 'Amateur Telescope Making' (!) and a book on electric clocks in the current Camden book lists give some information on making Synchronome clocks, but assume you will buy the castings from the Synchronome company (who are long gone, alas). For the UK people here, Hope-Jones was the originator of the time signal 'pips' on BBC radio... -tony