Here, it is assumed that you have a single momentary contact closure at the appropriate interval (30 seconds is common), and ideally that the contacts are not part of the electrical wiring scheme. This assumes that someone before you hasn't removed the contacts and actuators completely, and that you have the correct master clock. While mechanical (or electro-mechanical) systems can work very well, the master clocks that generated alternating current pulses can be extremely difficult to adjust properly. This article looks at how you can determine the proper voltage and current needed to make the motor turn, and ways that the alternating polarity signal can be created. In some cases, you might find the coil resistance printed on the outer insulation (or elsewhere), but much of the time there is nothing at all. In reality, all of these motors expect a current - the voltage is only a requirement to ensure that sufficient current will flow to make the motor turn 180°.

The latter can range from a few volts to 50V or more. Making matters worse, some of the alternating polarity slave clocks expect a specific current (perhaps around 200mA), while others are designed for a particular voltage. Even if you could see it, the IC is utterly inscrutable and nothing useful can be gleaned from it. The most prolific motor of all that uses this technique is the common quartz clock, but the method used to derive the signal is hidden from view, and lurks under a blob of epoxy resin on the printed circuit board. Some (like the Synchronome slaves) use a pulse of current created by the master, but there are many others that require an alternate polarity for each impulse. There are quite a few slave clocks appearing at auctions (both 'bricks & mortar' and online), but the biggest problem is how to drive them.

5 The Hard Way - Electro-Mechanical Switching.

Synchronome master clock serial numbers