Power Supply Systems
Implementing period power systems for the telegraph is easy in some respects, and difficult if not very practical in others. Since we understand that each station needs two power sources, the main line power either through the line from another station or a set of cells at the station along with a local power supply of typically two cups, then we can begin to create ways to build or simulate authentic power and power supplies.
Fortunately for us there is a great resource named L. E. (Ed) Trump who has developed a power supply system for telegraph demonstrations. His system replicates the line voltage and current that was used in the 1860’s. His plans are available on our SCARD site in the Telegraph Section. CLICK HERE As we all know, the “old guys” used chemical batteries like the Grove or Daniell cell to supply current for the telegraph. They placed the cells in series to get the necessary voltage. The voltage on the line was from about 60 volts and up. The supply needed to sustain a mainline current of about 50 ma. While it might be impractical to build a bunch of Cells (cups) for the mainline, it is quite easy to build two cups for a local loop.
We have many alternatives when it comes to supplying the power needed for the power supplies suggested by Ed Trump. The first, and my preference, is to use a 12- volt battery running an inverter, which in turn runs the power supply. I’ve tried that, and it works well. My power supply is a duplicate of Ed’s “low voltage” supply (about 60 volts or so). I also built his high voltage version, which goes up to 120 volts. It too works well on an inverter. The power supply, battery, and inverter along with an ammeter and rheostat all are housed in a period looking wooden box. Other methods include using a generator, or an extension cord to a current outlet available in most parks to supply current to the power supply.
As I mentioned, the local loop can be powered from a replicated set of Daniell cells. I built a six pack based on what T.T. Eckert described to his boss in June 1864. They work great. Copper sulfate is not bad as chemicals go, and it is the only chemical that is needed. An alternative is to use dry cells like hobby batteries, or lantern batteries with resistors. It is also possible to build a DC power supply running from AC mains that provides the three volts. Then you can place it along with the mainline AC supply running off the inverter. I have such a power supply and it too works well.
There are thus many ways to generate the power for the telegraph. If you simply use one or two 12 volt batteries in series for the mainline depending on the number of instruments on the line, that will work. However, the instruments will not have the “snap” that is desirable when operating with any kind of speed on the line. The old guys knew what that meant, and it is described in Pope, Prescott, and Shaffner. It has to do with a guy named ELI the ICE man.