Re: DC Power sources for a 1920's Synchronome master & Current Regulation?
OK, what I actually do is quite different as I have a large system with a distribution board etc.toggle quoted messageShow quoted text
If you have no risk/worry over power cuts, then a ‘wall wart’ type adaptor is fine. If you get power cuts and with to run through then, then there must be a battery involved. What I would (probably, and actually do for a single Silent Electric master running one salve dial) do for one clock is this;
Use a battery made up of AA cells (NiMh) - probably 4 cells if I was using no external slaves. Use a 6 Volt (or slightly more if you have an old one to hand - I often use old redundant mobile phone chargers) ‘wall wart’ in series with a resistor to trickle charge the battery (charge at about 50 mA or less). Run the clock from the battery, limiting the current to 300 - 330 mA with a suitable resistor. It is important that you think about getting the correct CURRENT - and use whatever Voltage needed to do that (typically about 4.5 Volts). It will run for some days, even weeks on AA cells in the event of a power outage, but they are the most plentiful variety of rechargeable cell.
D cells are fine, and I do run a Bentley clock on a single D cell, where it runs happily for over a year.
Synchronome didn’t usually have a variable resistor fitted (though some late ones do. Gents generally do have a variable resistor.