Movement record · Switzerland

Felsa 690 Bidynator

Partially verified

Automatic bridge calibre with bidirectional rotor winding

Technical specifications

Diameter: Approx. 25.6 mm
Height: Not recorded in the sources consulted
Jewels: 17 (variants differ)
Frequency: 18,000 vph (2.5 Hz)
Power reserve: Approx. 40 hours
Winding: Automatic, bidirectional winding
Setting: Pendant set
Escapement: Swiss lever
Balance: Monometallic balance
Complications: Centre seconds, Date in some variants

Identification features

Bidirectional winding mechanism marked with the Bidynator name in period material
Felsa calibre stamping

Known variants

Date variants
Later Felsa automatic derivatives

Servicing notes

Cleaning, lubrication, mainspring and pivot work belong with a qualified watchmaker working from calibre-specific documentation. Conserve original parts: replacing a worn component with a modern substitute changes the object, and refinishing plates or dials destroys evidence.

General guidance only. Antique movements should be serviced by a qualified watchmaker.

Historical significance

An early widely adopted bidirectional automatic winding system, which improved winding efficiency over single-direction designs.

Diagram

Schematic: plate and bridge layout. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

de Carle, D., Watch and Clock Encyclopedia
Period trade material catalogues and calibre reference compilations (edition-dependent)
Published manufacturer technical documentation where available

Where sources disagree, the disagreement is stated rather than resolved silently.