Alan's Latest Project - ECN Electrical Forums

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From a 1946 'Luchard, Paris' air compressor, now being renovated.
These pics are of the original 3 phase toggle switch, used as a direct-on-line starter for the induction motor. Best guess is the motor is around 1 hp, (the motor plate doesn't say). As you can see, the construction is crude, but even after nearly 60 years, it works perfectly. Economy with materials was essential then; the date stamped on the receiver, ( 2. 20. 46), is only 10 months after the Liberation of Paris. This unit was probably built along with the motor in Orleans. The motor company; Cie Generale d' Electricite, Ateliers (workshops) d'Orleans.

Pic 1: Construction mainly of resin bonded paper/cloth, ('Paxolin' 'Tufnol' ?) and bakelite or vulcanised rubber, mounted to a thin iron chassis . The original operating knob is missing:

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Pic 2: Wipers, rotor and contacts with spring snap open mechanism. The pillars are bakelite/vulcanite:

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Pic 3: Partial dissassembly, showing the 3 rotors separated by cardboard dividers:

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Pic 4: Further dissassembly, showing the wipers, contacts and rotors. The terminals are hollow brass with iron screws to clamp the wires ( more economy) . There is evidence of arcing on one wiper, and this may be why the unit had been replaced by a modern 'Telemechanique' starter:

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Pic 5: The original outer plate, made of 3/16" Bakelite. This fixed the unit into a housing cast into the motor body. The green paint is not original, ( it is also splashed onto the new starter). There is a very small possibility of markings under the paint- I will take it off carefully to see:

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I want to have this machine running for shop use, (I'm not interested in static museum-pieces), but on the other hand I like to retain original features in old machines. I'll renovate the switch and plate and replace it as a dummy for future reference.
I'll post more pics of this compressor project as it procedes, but right now I have to make some tables for a new swanky hotel bar a French friend is opening in July, so it'll be some weeks yet!.

Pictures and information submitted by Alan Belson.

And more pics from Alan!:

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I am progressing with the Luchard compressor, did a 220 psi hydraulic pressure test on the receiver to see whether it was worth continuing, which turned out ok. The pressure switch is a nice unit but I'm thinking of putting modern controls on for safety and because the reliability of 60 year old vital parts is always going to be questionable, particularly the old insulation! I'll retain all the bits on the machine, just not wired up. Ditto the safety valve!.

Pic 1: Reciever Pressure Test:

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Pic 2: Pressure switch, with cover removed:

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Pic 3: Opposite side view, showing contact lifting knob:

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Pic 4: View of contacts:

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Pic 5: Picture of compressor unit, as bought:

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If you haven't make sure you inspect the inside of the tank. 125-175 PSI in a tank like that has a lot of force. I seen after one blew apart it smashed a tool box, steel shelving, broke all the lights, cracked all the walls, went thru drywall & half out the sheet metal wall.

Tom

Tom,
I can't help but agree, mate.
I spent quite a bit of the first part of my working life filling and testing Steel Breathing Apparatus Cylinders.
Getting a bit off topic here , but we used to X-Ray them.
To have a BA Cylinder explode on your back, would be unthinkable.
Alan,
You compare the build quality of the Pressure Switch there and that of today, in some cases I don't think that there is any competition.
This stuff looks like it's hand-made?
Even to the extent that the castings, while you have to be careful with any cast stuff, look top notch. [Linked Image]

BTW Alan, have you had the motor to pieces yet?
I have a mate who is a motor rewinder by trade(Phil) and he has worked all over the world, he could give you a hand with sorting out the motor part of it.

It's very difficult to assess the interior condition of the receiver, as the only access is via 1/2" BSP bosses, ( luckily, pipe threads are one of the few things un-metricerisated by the Revolution! ) - I tried to get hold of an endoscope this morning without luck. Even then, how to interpret the implications of what I may see? Externally there is little sign of 'tin-worm', even under the skirt. The shell is welded up from 4mm (0.16") plate, based on some fiddling with 'L' shaped strip and a depth gage. Bearing in mind I put 220psi hydraulic pressure on, I think that the modest 90psi I'm planning will be safe enough. I thought about putting in some kind of rust proofing paint? bitumen? and swilling it about to stem any further corrosion? WDYT?
As to the pressure switch, yes, it is well made, and it weighs 7lbs 4oz in its socks! The contacts are really sound. My reservation is the diaphragm. If that looks sound/simple to replace I'll give it a go.
The unloader, (that's the little air-cylinder with the cranks off the switch arm in pic 2.) will also need attention, as its blowing lube oil into the unit. Also I'm not sure what's inside the adjuster boss (LH, bottom just behind the unloader). That looks ominously large for a 5/16" (8mm) thread adjusting screw- I bet theres a mechanism in there for re-start at lower pressure, (tripping the breakers).
Back to the bench, more anon!

Alan

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Here's where we are tonight, after a few hours in the shop. All the crud, rust and green paint removed, switch partially disassembled, and looking good for use on the machine.

Top Row, from L : Broken nipple, removed. Iron Union-elbow. Screws(4). Cast Housing. Rubber Diaphragm.
Broken nipple had sheared off in the receiver, both bits retrieved. The Diaphragm is a bit perished, but easy to replace, it's just plain 1/8" rubber/fabric/rubber and the local garagiste, M. Boitin, can supply a car-part for modification.

2nd Row, from L : Switch unit. Push Rod. Washers(3). Domed Piston. Outer Ring.

3rd Row, from L : Unloader Piston: Stem. Nut. Body. Remains of cork seal! Spring. Nipple. Union.
There is a part missing- the piston! This was probably a 5mm steel ball, and explains all the lube inside the switch.
The Union has a little seal missing and the pipe, (to the non-return valve) will be replaced.

Bottom Row, at L on box : Safety valve: Body elbow. Stem. Spring. Washer. Vent Cap.
This is in really good condition and only needs the ball end to be reseated with grinding paste. Re-usable!

Bottom Row, at R : Inside that 'ominous cast boss' : Stem. Spring. Captive bolt/flange/nut. Screws(2). Tab.
This was siezed solid, but eased up with oil. The Stem acts on the flip mechanism, and has a locking tab, so my guess is that this is the 'Off' trigger pressure adjustment knob. We'll see when I start the initial runs.

Alan first let me say that I think the fact you want to restore old items for use instead of making them museum pieces is great.

I never really understood restoring things to a point where they need to be placed in a display case.

Now that aside unless you can have the receiver inspected by a professional I would not even consider pressurizing it.

I spent 5 years as a maintenance mechanic and we would regularly see pictures of receivers that let go and the destruction they caused.

A receiver containing a compressed gas is essential a bomb waiting for the inevitable corrosion to weaken the steel to the point it lets go. It is unusual for these tanks to simply start to leak.

One day it is holding pressure the next day it has gone into an earth orbit.

Being the clever guy you seem to be I would bet you could hide a new tank somewhere else still using the old compressor leaving the old tank under it.

Whatever you decide best of luck to you.

Bob

Bob,
That is an absolutely brilliant idea, and I've been on the net looking for air tanks(?)/ receivers already! This will remove any nagging doubts about the safety aspects of the renovation.
Thanks,
Alan

I am glad you see the problem too.

With a quick search I found these photos of a car that had a SCUBA tank let go in it.

Now I beleive SCUBA tanks run a high pressure but they also have a much smaller volume.

[Linked Image from diveshop-pr.com]

I bet the owner of this tank was glad it was not on his back.

Many more pictures here.

http://www.diveshop-pr.com/pages.dir/engl.dir/tankexplosion.html

Anyway good luck and stay safe, Bob

Yay, Bob!
I second Alan's sentiments. I had thoughts about the safety of that tank too, but you've come up with a way cool, safe, fix.

Good work [Linked Image]

Thanks electure. [Linked Image]

Where I worked we had many air receivers some as large as 500 gallons and running 125 to 175 PSI. The care of these was a great concern.

We had a picture of a 3 or 4 bay garage that was made of concrete block that was literally two thirds leveled by a receiver explosion.

Compressed gases are very dangerous, we also had hydraulic accumulators that operated on compressed nitrogen. Think of these as storage batteries for hydraulic pressure.

The hydraulic pump could be off and there would still be full line pressure (2000 to 3000 psi) in the hydraulic system. This could easily kill the untrained.

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The hydraulic pump could be off and there would still be full line pressure (2000 to 3000 psi) in the hydraulic system. This could easily kill the untrained.

Whoa Bob !!,
I wouldn't disagree with a statement like that at all. [Linked Image]

Bob,
Were the nitrogen accumulators for high-pressure diecasting of aluminium by any chance? I worked for a company that made these machines, (Alfred Herbert, long since kaput) and the Foreman, Fred Bignold, had a party-piece where he put a nylon shirt ( remember those things!) into the injection sleeve and fired it into a test mould at 4000psi. The result was unbelievable- it came out as a disc 2" in diameter and 1/2" thick, and you could see the buttons inside it. A quick manipulation, and voila! the shirt was resurected- it was a bit creased though! [Linked Image]

PS. as is the vagaries of this modern mad world, it seems it's cheaper to buy a whole blinking compressor than just a receiver! Still looking!
Alan

From Alan:

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Took the pot off the compressor during dismantling, and dropped it on the floor. Oh! #***~?#*!! Never mind, my oldest son is making an exact copy in Gloucester, ( because his ma told him to! ), so there will be a slight delay while his CNC machines whittle another one from a solid chunk of Meehanite.

[This message has been edited by Trumpy (edited 06-23-2005).]

The Latest from Alan!:

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Hot off the machines, the new cylinder barrel to replace the one I broke. I kept to the spirit of the renovation and spent an additional US$75 having the fins machined axially, rather than turned like a motorcycle pot. It's being shipped to me shortly via a visitor. I'm going to drill and tap the mating holes using the existing parts as jigs, and do a bit of filing and sinking to blend in the sharp corners. We used a medium carbon steel in the end, as cast iron proved too expensive. I'll use a moly oil-additive to prevent ring pick up till it's run in, unless any gasoline-head members think different!.

Thanks Alan. [Linked Image]

If it's well polished/burnished it shouldn't really need running in.