Electric wall clock by Cotna

Square Metal case, painted, with polished aluminium rim to dial aperture. Size: Dial approx 8.5" across. The hands can be adjusted from the front of the clock by a knob on the minute hand shaft.

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.

This clock has a movement with plated steel plates and wheels. The eddy current motor has a plated rotor. When the spring is fully wound a felt pad touches the eddy current rotor which restarts after a short time as the spring unwinds. Click for a view of the movement