A week on the tools - including a nice little job with a puzzle for you

[Lucien Nunes]

Well it's not often that I get to do a solid week of electrical work these days. Most of my time is office/lab/workshop based, in the field it's mostly electronics. But last week I did Monday to Saturday, six days and two nights, about 100 hours of non-stop-sparking. The main job saw the core team of four of us back together that first worked as a unit doing theatre installations back in the 90s: Richard, Steve, Jason and myself. Anyway I digress, it's not this I wanted to talk about, it's the overnight job.

An old piece of kit on our round (we've got a lot of those) still working but in need of maintenance and in our sights for safety improvements. Not sure when it was installed, I think it's early 1930s but just possibly 20s as it is part of something that was installed in 1925. Peter and I had originally planned to overhaul this unit and upgrade its safety features while replacing the very ramshackle wiring to it that has been modified over the years. However, for various reasons, we decided it was better to decommission it and leave it in situ as a museum piece, and fit a new one alongside. This we tried to do last week but one component on the replacement was damaged in transit so we have to return there tonight to complete.

Let's begin with a pic of a little bit of the inside. I made a video of it before disconnection and this will be online in due course. If you are lucky you will also get to see the whole machine in operation, which is is fine working order. The pink bit is me, pointing out the accumulated wear from 85 years of use.

 

[The Ghost]

It's a clock.

 

[Pete999]

Voltage Stabiliser.

 

[The Ghost]

Voltage Stabiliser

Sigh...if you look carefully that is what I said.

 

[Wilko]

No, I'm sure thats a hand in there ...

 

[freddo]

I've no idea but it looks interesting! Everything modern is so boring!!

 

[Marvo]

Looking at the depth of the arc damage on that contact I'd say it's only got about another 200 years of useful life left in it.

 

[dmxtothemax]

Are you teesing us ?
What is it ?
it's obviously some sort of switching arrangement
but whats it in ?
Stay tuned folks
same bat time, same bat channel !

 

[marconi]

A thermostat - normally closed which opens when it exceeds a certain temperature. The copper rod expands as it warms up and rotates the contact bar to move the 3 sets of contacts. The component which has 3 red wires going to it and at least 2 bare wires (an earth?) is connected across the 3 thermostat contacts which makes me wonder if it is some form of arc suppression especially since the contacts have so little arcing damage. Each upper contact has 2 red wires - one going to the arc suppressor and the other away to the supply/load.

 

[Lucien Nunes]

Interesting ideas. It's not thermostatic but it is sort-of barometric. The company that supplied it also made water-engines. I've just got home from finishing the job, all good but I could use some shuteye before putting up more pics.

 

[dmxtothemax]

Some might say it's over kill
when you consider that they are so small and cheap now !
But he fact that it lasted many decades speaks volumes
of the times when quality meant something.

 

[Lucien Nunes]

Here's another view of the bottom bit. You can see a piston in a cylinder and some more contacts. The black compartment at the bottom has a piece of 3/4" plastic hose connected to it (originally rubber). Some facts:
Maximum current 25A, typically 4-7A according to usage.
Made in London, but much of associated equipment made overseas.
Located in basement of prestigious retail store in the West End.
Small disused DC generator stands nearby.

BTW the 1.5mm² red flex in the yellow crimps is not my work!

 

[The Ghost]

Air conditioning system/ventilation.

 

[gazdkw82]

is it a dolce gusto coffee machine?

 

[Lucien Nunes]

Ha ha, I could have done with a coffee at 4am when we were testing the installation. There is indeed a remote connection with 'dolce' but not with 'gusto', at least not in the Italian meaning.

 

[Pete999]

It's a clock.

Oh it's a CLOCK Voltage stabiliser, so sorry

 

[marconi]

As the equipment is found in a basement in London, is this a device which uses the idea of a manometric head to respond to rising water table? The lower compartment is a pressure chamber, connected to the upper part of the manometer via the pipe, and containing a piston to move the contacts above it to start a pump? The pipe being inserted into a deep hole and then filled - but not completely- with water to leave a volume of air which can be compressed inside the black compartment.

 

[drzsta]

So some form of pneumatic switch but for what I'm am not sure? Old refrigeration control?

 

[Pete999]

Part of a Saline genset load bank

 

[Pete999]

A Wig Wam for grinding smoke

 

[Lucien Nunes]

A more comprehensive view. More info:
Does something, then does something else.
Hose connection has to do with timing second thing relative to the first.
Has an interlock to prevent it doing the first thing again until the second has been undone.
Modern replacement doesn't need the hose, has electronic module instead.

 

[Pete999]

Part of a slip ring wound rotor resistance bank for speed control?

 

[DPG]

Intriguing. Got me stumped that.

 

[Devonchris]

Switch gear for a lift.

 

[Lucien Nunes]

Not a lift. Pete's closest so far, there was a slipring version of this with the same basic mechanics but this isn't it. I'll put up a video later when I'm near the laptop. FWIW I was just looking inside a British Klockner unit from the 1960s that uses a Rotherham escapement timer instead of the hose gubbins.

Useful fact: Once this unit has gone through its sequence and the user begins to operate the equipment, it produces something that is distributed into the building through grilles on the wall.

 

[Devonchris]

OK it's a water misting system located in the food hall in Harrods. Helps to keep the produce fresh. First cycle starts the pump. Second cycle allows use when correct pressure is obtained.

 

[NDG Elecs]

That's a pre-production prototype for the first iPod I reckon.

 

[SparkyChick]

I'm going to take a punt at a Star-Delta starter for an air blower, with the hose providing pressure feedback that is used to switch from start to run.

 

[DPG]

Smoke generator. Builds smoke up then releases it.

 

[Lucien Nunes]

Well done SC you're spot on. It's a star-delta starter for a 5hp motor on a 4-stage Discus organ blower, that uses pressure from the second stage to operate the changeover. The blower supplies a 1925 Wurlitzer cinema organ in what used to be the New Gallery in Regent St. until the 1950s. It has been a store for years but the organ is still there and is kept in good order although seldom heard. What comes through the grilles into the auditorium is of course not the air itself but music. Vids later...