Re: DC Power sources for a 1920's Synchronome master & Current Regulation?

John Hubert

OK, what I actually do is quite different as I have a large system with a distribution board etc.  

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.


On 2 Mar 2021, at 10:07, Chris Wollaston <chris@...> wrote:

I'm still in the process of setting up my first Synchronome master and fortunately have found a supplier of a pukka pendulum & bob to replace the incorrect ones that came with it.  Now I'd welcome advice on what owners use for the DC supply for just the movement & it's integral clock?  I've been using a mains adaptor giving 5.2VDC at max 1A which I believe is too much as Miles mentions the set up voltage is 4.5VDC and 350mA.  My architectural case did not come fitted with a rheostat and again Miles doesn't show that 1920's models with any fitted current regulators inside the case.  Would 3 x D cells in series be adequate and last a decent time span, say a year+ and how do readers regulate their current? Rgds, Chris in E Sussex.

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