Long before the first production 500 electric movement appeared, Hamilton had developed various prototype movements during the early 1950s. Some were based around electro-magnets (EM-1) while others had permanent magnets (PM-1); both designs had their followers, but in the end, the permanent magnet design won on electrical efficiency grounds, and PM-1 became the ancestor of all production Hamilton Electric movements (500, 500A and 505).
There were many problems with PM-1, so further prototypes were developed to refine the design; Model 1 went through Mark 1, Mark 2 and Mark 3, but in 1953, the research group produced the Model 2. This was a major re-design and was much closer to the final production 500 movement.
The Model 2 was a “wear test” model; initially there were plans for 25 but ultimately, only 23 were made. They were cased and given to senior Hamilton Executives to wear on their wrists for a period of time. This movement differs from the production 500 is several ways: it uses an epoxy resin balance, has large flat magnets and a primitive contact system.
The Model 2 movements generally performed quite well although the contacts were temperamental and the epoxy resin balance were susceptible to changing humidity. For a full description of Hamilton’s early work on the development of the world’s first electric watch, I suggest you get hold of a copy of René Rondeau’s book “The Watch of the Future” — details are on my Books page.
A fellow UK Hamilton Electric enthusiast, Dan Mitchell, kindly gave me one of these extremely rare and unique Model 2 prototypes! It is Serial Number 19 (the example shown in “The Watch of the Future” is Serial Number 17). The following photographs are of my Hamilton Model 2 Serial Number 19 (out of a possible 23). Many thanks Dan, for passing this wonderful piece of Hamilton electric watch history on to me.
The next set of photographs shows the next development of the electric watch. Another prototype from 1956 but this one is clearly a finished product and is marked as a Hamilton 500 movement with 17 jewels. It is the latter that identifies it as a prototype; 17 jewels means it has the double-indexing system which proved to be seriously flawed and, as a result, it never made it into a production watch. Instead, the index system was re-designed and, as a bonus, the movement was simplified and the jewel count dropped from 17 down to 12.
This example, which has a movement number of 615L, is embedded in plastic. In 1958, the marketing department took about 20 of these 17J prototypes, embedded them in plastic and presented them to museums in the US, England and Japan. Sadly, my example has been separated from its presentation board:
Hamilton produced all sorts of gifts to promote The World’s First Electric Watch.
These three photographs show a 500 demonstrator given to Hamilton stockists; this one is a little rarer than most since in contains the unreleased 501 movement. It is a fully working movement!