History of mains voltage used in France

[gblades]

Ok I have a piece if old equipment that I am restoring. I believe it was designed for the French market and produced possibly any time from around 1920.
Today France uses a 240 volt (or close enough) system but I have heard that in the past it might have been different?
The resistance of a coil of wire measured and compared against a schematic would certainly indicate it could be designed for a lower voltage supply.

[Simon]

France was 220V I think, only the UK was 240V but around 20 years ago they decided to split the difference and officially call it 230V which with the tolerances allowed falls within both. You will note a lot of your modern mains gere is 230V.

I am not sure what they used in the further past though as i remember my dad having old radios that almost had a selection for each country.

[gblades]

Thanks. Just corrected a typo in my original post. It should be around 1920s not 1820s!

[Koen]

Early lines were 110V.

[StillTrying]

The resistance of a coil of wire measured and compared against a schematic would certainly indicate it could be designed for a lower voltage supply.

If the coil of wire is a heater, its cold resistance could be much lower than when it is hot.

[Simon]

I'd go with 110V and increase if it seems to need it.

[gblades]

It is one of these https://en.wikipedia.org/wiki/Violet_ray so it should be cold.

[StillTrying]

It is one of these https://en.wikipedia.org/wiki/Violet_ray so it should be cold.

My grandfather was into some of this stuff, - but I was too young at the time, some of his stuff was just
12 Volts operated.

If it works by energising the coil, which then de-energises itself to produce a high voltage back EMF, then it's resistance will seem a bit low, most of it's resistance when working will be provided by it's inductance.

The one in the picture doesn't look safe to connect to any mains voltage to me!

[Enigma-man]

A lot of radios were battery powered back then using  22.5 and 45 Volts I think along with a giant 1.5V for the tube filaments.
According to a video I saw a doctor would take the Violet Ray device with him on house calls.  For portability, you would have
to ask what was available at the time and it might have been one of those 22.5 volt radio batteries. But, who knows ?
Few people had electricity in their homes in the 1920's, especially rural areas, so the doctor couldn't just walk in and hunt for a wall receptacle
so it's doubtful that it was line powered. 
A DC source sounds about right but at what value ?
More research needs to be done on your part.
I wouldn't hook it up to the AC line just yet.   

[gblades]

Someone sent me this diagram and the measured values in mine were close enough that it should be on to run for a few seconds. It worked but the power output was low. I replaced the capacitor and the output was much higher (too much!). Hence looking at the history and comparing the coil resistances it seems that it might be designed to run off 110V instead.
There were lots of people making these things and they were all mains powered. Later ones could be switched between 110 and 220V.

[Enigma-man]

You could adjust the AC input with a Variac until you found the proper voltage.
Looks like your unit wasn't meant for portability as it is AC powered.
Yesterday I found a YouTube video of someone using a 4.5 to 30VDC power supply to power
what he had.  Looks liked different versions were available at the time.
This setup reminds me of a car ignition coil stepping up the voltage to several kV.

[StillTrying]

This setup reminds me of a car ignition coil stepping up the voltage to several kV.

Yep, you only the need an ignition coil, 555, a power transistor and 12VDC. 

[savril]

From french wikipedia : https://fr.wikipedia.org/wiki/R%C3%A9seau_%C3%A9lectrique#Les_premiers_r.C3.A9seaux_.C3.A0_courant_continu)

The voltage was normalized to 220V only in 1956. Previously, it was mainly 127V depending which local network you were on.
After that , in 1986 the voltage was increased to 230V.

[JacquesBBB]

Are you sure it was powered on the main ?

I  know some old devices that were powered with batteries.
It was I think quite common to have refillable battery.
I have one of these  that come from a grand uncle  and  had 24 cells that you can use
at will   from 1 to 24 in series.
It  has an ammeter that is patented from 1904, so I believe the battery is from around 1910.

Electrods are zinc and carbon, and solution sulfuric acid + mercury sulfate (not easy to obtain now).

Similar to this one
http://www.pierre-billon-antiquites.com/project/pile-electrique-ancienne/

[gblades]

I am pretty sure. It does work on 240V but there is excessive arcing on the interrupter contacts. If it was designed to run on batteries I would expect the operating voltage to be much lower and it probably would not have survived running off 240V.
Also the coil resistance is around half of the typical value used on the 240V variants.
I have arranged to borrow a 110V isolation transformer (as used on construction sites etc...) at the weekend so I can see how it behaves on the lower voltage.

[gblades]

Tested it on 110V at the weekend and it does work perfectly.


So now I need to convert it to run on 240V. I have seen voltage adaptors which plug into the wall and have a USA type 110V socket on the front but I don't know how they work and I would rather have a metal box with a transformer in for example where I can fit a filter, panel fuse holder and a switch.
I will have to see what transformers are available. The unit itself is around 40W.

[StillTrying]

A broadband spark transmitter.