The movements are characterised by:
- Balance Wheel with integrated Coil (moving coil)
- Permanent Magnets in movement plates
- Mechanical contacts
As the left and right hand side of the coil pass over the magnetic field of the platinum-cobalt permanent magnets, the contacts are closed and the balance/coil receives an impulse from the electromagnetic force. The balance spring ensures there is a reverse impulse and the cycle then repeats itself.
Unlike the Fixed Coil System, Contact Controlled movements, these have no other electrical components: just the coil, contacts, magnets and battery. These are the true electric watches.
The first set of photographs cover the Hamilton 505. The movement features in most of the watches in the Hamilton section:
This next photograph shows the UMF 25 which first appeared in 1963 but was gone by 1967, being replaced by the similiar UMF 26 which continued through until 1973. The UMF 25 is very similiar in many ways to the Hamilton 505. It features in the Champion Electric watch:
Below we have the Porta PUW 1001; a West German movement from 1969.
Finally on this page is the cheap-and-cheerful Timex M40 — made in large quantities. But it looks so boring , with it’s pressed steel plates, compared to the Hamilton and UMF, but this example keeps very good time.