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...

 

[SparkyChick]

Neat. I take it it's an electric action from the console to the wind chests, not a mechanical track rod. Would be great to see some pics of the wind chests, controllers and console if you've got some.

Love organs (keep it clean boys ), had the pleasure of working on a church organ or two in my time and they are just awesome.

 

[marconi]

My last stab - pondering on 'dolce meaning sweet' - is it a scented air system for which your images are the controller? Used in the days of London smogs perhaps? The compartment is loaded with scent the blower can be started and when it has all been used up the mechanism shuts down the blower.

 

[DPG]

Nice one SC. Not bad for a girl ;-)

 

[SparkyChick]

I'm looking for the 'Fisticuffs' rating @DPG

 

[DPG]

I know you've got a good sense of humour. I think I'm safe!

 

[Lucien Nunes]

Cinema organs are quite different to church organs; created to take the place of orchestras they have an enormous variety of sounds to offer and ingenious ways to enable one player to control them all at once. At the console of a good cinema instrument, an artist can express any human emotion from pure delight to utter despair, with any amount of presence from barely-there to overwhelming. He or she can tell complete stories without words, can be a full band, a soloist, an accompanist or an entertainer, in any style from jazz to classical to pop to epic movie soundtrack. But again, I digress.

Yes, the action (the bit between the console and pipes) on all cinema organs is electric and/or electropneumatic and on a large instrument fiendishly complex. This one is not huge but still has around 500 cores in the console main cable, all of which operate relays in the pipe chambers that sort out which pipes are to play - there's no direct mapping of keys-to-pipes because each pipe in a cinema organ serves multiple duties. As you've asked, I'll try to sort out some pics of the action, it does need a bit of explaining though as the relays and binary logic switching elements are unlike any you'll see in regular electrical work!

Here's the blower to look at while my video of the starter uploads...

 

[Gakure]

Transfer switch

 

[Lucien Nunes]

First video up, see the old starter operating here:

And here's a pic of the new starter with the old one behind. The box above the starter itself houses a supply monitoring relay that gives extra protection to the 85-year-old motor against e.g. singlephasing and regeneration when running very light, allied with the thermal overload relay in the starter. Also in there is a contactor for the 10V 30A DC power supply unit that feeds the electropneumatic action of the organ.

 

[Lucien Nunes]

I should have explained how the starter works. When the blower runs down at the end of a run the actuator rod falls. Its striker engages the slotted black contact operating pawl and pulls it down under the weight of the rod and piston, tensioning the two long springs. Once down, the tips of the pawl lock into the rectangular slot in the catch at the front, holding the three moving contacts (connected to one end of the windings) against the bottom row of fixed contacts which link them into star. To start, the 3-pole line contactor at the top engages and holds, and the blower runs up. When there is sufficient pressure the actuator rod rises and once the striker is clear of the pawl a ramp trips the catch off. The long springs pull it up, rocking the contact bar to open the star contacts and close the delta contacts (connected to the supply) in the top row. The speed of the transition is regulated by the dashpot cylinder to the left of the rod. The ramp holds the catch open and with it, the interlock contact. This disconnects the start button so that if the line contactor is released, it cannot re-operate until the blower has run down and the changeover mechanism has reset to star. I didn't show the stopping part of the cycle in the video as it takes nearly two minutes, due to the huge moment of inertia of the blower impellers.

 

[delano]

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.

View attachment 37047

It looks like on old isolator.

 

[Lucien Nunes]

Time to unveil the new starter in operation. In the starter itself to the very left we have the timer, which I set to make the transition a little later than the pneumatic one was set, so that the blower is very nearly at full speed and the current a few amps lower when it happens. Then there is the overload relay, in the delta loop so set at FLC/sqrt(3) or about 4.5A for a 7.7A FLC. Then the line contactor, with the start button mounted on top, the delta and star contactors with a dual N/C interlock contact mounted across them (there's a mechanical interlock hidden inside too) and the isolator. In the box above is the monitoring relay and the auxiliary supply contactor slaved off the line contactor. The two sets of three brown 2.5's at the bottom are the two ends of the windings.

When you press the start button, provided the monitoring relay and O/L are normal, you start the timer which outputs a feed to the star contactor coil. This operates and its aux contact extends the feed to the line contactor which also operates, holds via one aux contact and bypasses the star aux with another. This sequence, rather than making the line contactor hold directly, proves that the delta is out before anything can happen, as an operated delta would prevent the star operating both electrically and mechanically. When the time elapses the star coil is de-energised, releasing the interlock and allowing the delta to operate.

Music next...

 

[Lucien Nunes]

And here's the result, including a brief musical demo, which reveals the console and its location. Don't play this through a tinny phone speaker, try it on the computer with the real speakers on. It's only a mobile phone video but you need a bit of bass to get the proper effect.

One day I will make a video of how all the organ electrics work...

 

[freddo]

Nice write-up, I still prefer the old version though...

 

[Lucien Nunes]

NB for anyone who hasn't spotted there's a brief musical demo in the video above^^.

Me too Freddo, but there were issues that needed addressing such as disintegrating rubber parts, difficulty of integrating a retrofit thermal O/L (it originally had none) etc meant that the starter would have to be considerably reworked if it were to remain in use. We preferred to conserve it for posterity rather than tinker with it and still possibly not have an ideal solution. Organs are expensive enough to maintain and if, like this one, they are only heard occasionally, one does not want an avoidable technical hitch to render the whole thing unplayable at a critical moment.

OTOH, amongst the old starters still at work in our sightlines there's a similar unit by the same makers that we don't plan to replace any time soon. It's the version for wound-rotor motors that puts the stator DOL but cuts out the rotor resistance in a couple of steps with rising pressure. This is on the much larger blower feeding the 1936/7 Southampton Guildhall Compton, one of the largest instruments of its type in the UK with two 4-manual consoles controlling 50 ranks of pipes (the Wurlitzer in this thread has 8). The motor is 17.5hp, 24A line at 400V, with a 3-phase 212V 38A rotor.

 

[DPG]

Very nice. Didn't realise the motors were so big for these things.

 

[SparkyChick]

They need to be, they can use huge volumes of air.

Pipe organs are just awesome pieces of engineering, and working on them was one of the best things I've ever done. Removing an old tracker (I think that's the right term for a purely mechanical linkage from console to wind chest) was one of the saddest, but many of the larger pipes got a new life as a pedal rank for a small village church organ so it wasn't all bad.

 

[Lucien Nunes]

These organs, designed to play music of many genres, have a lot of orchestrally voiced stops over and above the 'traditional' organ tones, some of which require mugh higher wind pressures. They also use what is termed 'extension', which allows each rank of pipes to do the work of two or three in a church organ by sounding more pipes per rank that the organist has fingers, so the wind volume consumed is higher as well as the pressure. A modest-size cinema organ therefore needs a blower more powerful than a very large church organ, which is more likely to be in the 3-5hp range. The very largest instruments sometimes have multiple blowers, the largest single blowers in the really colossal instruments are in the order of 100hp although these tend to be over-specced and rarely run anywhere near that load. Southampton is very well matched to its wind load and does perfectly with 17.5hp what a USA builder might have specced nearer 30hp.

 

[SparkyChick]

All I can say, is if you're ever in my part of the world working on one, I'd love to come along and take a look

 

[DPG]

All interesting stuff. There's a fairground museum on the east Yorkshire coast called 'The Scarborough Fair Collection'. They've got a few wagon mounted pipe organs there, along with various old fairground rides. Including a nice set of old dodgems. The good thing is most things are up and running and you can go on them which is nice. And they've got a working cakewalk. Some nice paintwork. Great place - worth a visit.
Of course, all you southerners will need a passport to visit yorkshire And I will personally check you over.

 

[SparkyChick]

Used to go to Scarborough on hols as a kid. Hire one of the beach huts for a week and try and ride the funicular near the Spa as many times as we could

Do Midlanders (with honorary Welsh status) require passports? I didn't the last time I went to Sheffield to see the fire service, but that was official business