The master clock is in the hall and as well as the 7” slave on the case door there is an 8” slave on the adjacent wall.  It makes it easier to explain how the clock works to visitors.

Ian cleaned the master but also put a resistor in parallel with the operating coil to give the slaves a longer impulse.  

He put a diode across the contacts to reduce arcing and a variable resistor in series with the slaves to adjust the voltage.  

I run the clock from a 12v caravan battery with a trickle charger.

Master Clock  |  Bathroom Slave  |  Kitchen Slave  |  Study Slave