If you’re here you probably know that in the 20th century Zenith made some brilliant watches, but did you know they also made clocks? Recently I serviced this electromechanical clock which is part of the collection here at The Clockworks, where I am based. It is a weight-driven mechanical deadbeat regulator with a feraris motor to keep it wound. This interesting feature is constantly trying to wind the clock but is stopped by a break once fully wound. The feraris motor has very little torque so is easy to stop and start, but requires a very delicate series of wheels to lift the weight.

Because the clock is constantly being wound, it can have fewer wheels: usually, the great wheel is present to give a clock a duration (time between winding) of eight days, or with an additional intermediate wheel, one month. The Zenith has only a centre wheel with the driving force, a third wheel and an escape wheel. This reduction in wheels will result in more consistent power transfer and thus better timekeeping as well as removing the responsibility of remembering to wind the clock. See the end of the post for a video of this in operation.

Behind the movement is a simple board with a few options for different types of connections. The clock natively outputs seconds pulses, and 60-second pulses. It also has a 240v connection for the feraris motor.

A feraris motor is a large disk of soft iron straddled by a mains driven coil. It is a seperate unit bolted beneath the clock movement.

Multiple Wheels and pinions reduce the required torque output from the motor and a simple gravity ratchet stops the mechanism from going backwards. The clock utilises a Huygens Endless Rope to facilitate constant winding.

The pallets are made from a casting, and forego traditional elegance in favour of technical superiority; their shape will make them incredibly strong and inflexible.

The escape wheel which rotates once a minute has this additional wheel with a long ruby pin. This activates a very delicate switching mechanism for one second each revolution.

You can see the beautiful finishing of the clock here. A combination of Cotes de Geneve and spotting is complimented by screwed down chatons holding clear rubies.

Below you can see the feraris motor train moving and winding the weight back up after setting the clock up. Normally, as this will run as soon as the weight drops enough to release the break, the weight would not drop this far, unless there is a power cut.