Interesting things turning up as I tidy the electronics lab...

[Lucien Nunes]

After being on the road day and night for ages, I've got a month of solid R&D / workshop-based projects to do so I am having a general sortout here at the workshop and especially the electronics lab that has been piled high with odds and ends.

Oddball No.1. Have a look at this tumbler switch. Just an old lightswitch, right?

 

[snowhead]

Judging by the comment, it's gonna have a Mercury switch or something unusual in it?

 

[Lucien Nunes]

No mercury, just ordinary contacts. But look at the size of it now I put the coins and card in for scale

 

[telectrix]

master switch for the tardis?

 

[tazz]

Deep patterass aswell, would say its a high current switch, for stage lighting

 

[PEG]

I have seen one in operation,a few years ago,in a hotel on Anglesey,it operated all the communal lights,on 3 or 4 floors,if i remember correctly.

It instigated one of those "Pheonix nights" moments,where Paddy was not sure if they were dwarfs,or far away...:smartass:

 

[Lucien Nunes]

It's an early example of an intermediate switch, that can be used as a general purpose double-pole changeover, made by Lundberg. They made a range of special-function 'Marvel' switches and promoted improved switching schemes e.g. for multi-circuit light fittings controlled from multiple points with a single control, even providing booklets to show how to connect them up. This one has a sticker on the back showing its use to reverse the polarity of a DC circuit, e.g to reverse a motor or stop fluorescents blackening at one end due to mercury migration on DC mains. But by linking the each pole's N/O to the opposite pole's N/C you can use it as an intermediate.

Of the three moving contact blades on each side of the mechanism, two are connected together and the third connects to another blade hidden deep in the ceramic base, that swings up into the fixed contacts instead of down as usual. You can just about see one of them to the left of the + terminal.

 

[Lucien Nunes]

OK, next.

Two switches and a socket. Nothing funny about the switches, just SP 1 way. Follow the wiring:

L/H Switch: Incoming feed, loop out to the R/H switch, switched feed to socket,
R/H Switch: Loop in from L/H, loop out to next point, switched feed to light.

With me so far?

 

[tazz]

Dimmer switches

 

[Lucien Nunes]

No, just ordinary waterproof ones. It's the wiring that's interesting.

Look at this pic, see how it loops through as I mentioned above. Into one switch, loop to the next, loop out. Then a switched feed from each switch, one to the socket and another to a light.

But look where the cable end is stripped, it's single core. It's all single core. So where's the neutral for the socket?

 

[tazz]

Without a neutral...I can only think of phase control now using the rheostat switches....?

 

[Lucien Nunes]

No electronic gimmicks - much too old for that (1920s).

Examine the wiring system and my comment that all the cables are single-core. Both switches and the socket have had a brass plug with three spouts fitted in their conduit entries. The switches have a cable in each spout but the socket has just one cable, while the other two spouts have been flattened and sealed (two stubs visible in previous pic.)

This pic of the inside of the socket shows not only the function of the ring pull under the socket (opening the porcelain shutter) but also how the connections are made. One side has one rubber-insulated core, the other has two uninsulated cores twisted together, Where do they come from and why are they uninsulated?

 

[Barry White]

looks like theres been another single going into the socket looking at the markings on the board.

ps was this from a farm? seen a few like this on old farms

posted this as you were posting Lucien

 

[Lucien Nunes]

Nope, no other cables, this is exactly how it was installed. No idea where it came from, we saved it as an example of the wiring system. It has both a generic name and this particular one has a brand name.

 

[Barry White]

are the singles lead sheathed or kucho (not sure how its spelt) its a form of metal sheath

 

[Kamikaze]

To me that looks like the Carter switching system. The neutral would be on the L/H Switch opposite the incoming feed (The terminals that are normally used for the strappers). But you have stated that they are one way switches and that is baffling me.

 

[tazz]

This is really interesting, can only think the cable is micc, and the uninsulated cable is the copper sheath. Are they waterproof switches or switch rheostats, like the old external ones used in public buildings...?

 

[Barry White]

To me that looks like the Carter switching system. The neutral would be on the L/H Switch opposite the incoming feed (The terminals that are normally used for the strappers). But you have stated that they are one way switches and that is baffling me.

not heard of that method just had a look on google interesting unconventional method frowned on today thanks every day is a learning day

 

[davesparks]

Is it just plain old concentric wiring?

 

[Dave OCD]

It's a PME/TNCS socket from long ago with combined neutral/earth at the socket ??!!