

Electric wall clock by Lepaute
Ref No. 192
Click for movement
Case: Octagonal Metal case, painted. Size: Dial approx 6.25" across. The hands can be adjusted from the front of the clock by a knob on the minute hand shaft.
The Ferraris type Movement: This is a French movement, not found in the UK so far as I know. It consists of an eddy current motor running from the AC mains and winding a small spring. The spring powers the clock which is a standard mechanical type with a platform balance.
This construction has several advantages:
1) The spring will power the clock for a sustantial time if the mains power fails. On test the clock ran about 30 hours before stopping.
2) The eddy current motor does not require a closely controlled frequency. It will operate over a range, stated on one model as 40-60 Hertz, so the clock still keeps time even if the frequency varies,
3) No elaborate switching is needed for the motor. The eddy current rotor has little power and can be left stalled when the spring is fully wound.
Movement: This clock has a movement with brass plates and wheels. The eddy current motor has a copper rotor of small size. So far as I can see the eddy current rotor is left stalled when the spring is fully wound and it restarts after a short time as the spring unwinds. Click for a view of the movement