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The Encyclopedia of Horology

Clock type · Precision

Electric Master and Slave Clock Systems

Partially verified

Systems in which one accurate clock distributes impulses to many dials.

Movement & mechanism

  • A master clock closes a contact at a regular interval, commonly every half minute
  • Slave dials advance by an electromagnet and ratchet on each impulse
  • Batteries or mains supply power, and the pendulum is electrically rewound in better designs

Identification

  • Slave dials with no independent movement, only an impulse mechanism
  • Wiring to a central master clock
  • Master clocks frequently survive without their slave network

Terminology

  • Master clock
  • Slave dial
  • Impulse

Known variations

  • Synchronome, Gents and Continental systems

Collecting notes

Originality decides value and interest: check that movement, dial and case belong together, and prefer honest wear over refinishing. Movement work belongs with a clockmaker; cleaning a dial or case yourself commonly destroys the evidence that dates the clock.

Diagram

escape wheelpallets and leveroscillator
Schematic: escapement arrangement. 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

  1. Britten, F. J., Old Clocks and Watches and Their Makers
  2. Loomes, B., reference works on British clockmakers (edition-dependent)
  3. Museum catalogue descriptions of comparable examples

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