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Darkwood

mystery device1.pngmystery device 2.png This is out of an old Russian lathe it has 4 contacts on it 2 x NC and 2 x NO it has a coil and on top it has a sealed oil filled reservoir.
What is its function!

Spoiler alert!!! Answer in post 9!!!
 
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It's very pretty,i could do with it in front of me......Is the oil filled resevoir affording cooling to the coil via structure? I have seen many devices fitted to old eastern european gear and they do not tend to have anything which is frilly or non-essential.
 
No the oil reservoir provides a function and can be adjusted to suit its a mechanical operation and has nothing to do with cooling.
We can of course establish this is a relay of some nature but it affords an extra function when the coil is de-energised.
 
Il let the cat out of the preverbial bag so to speak as any mor clues would give it away...

Its a timer relay with true off delay..... When the coil is energised it pushers a lever onto a micro switch to change the relay states, when the coil is de-energised the lever stays in position held by the suction of the oil reservoir which slowly releases in accordance with the speed at which the oil pressure is released (adjustable with a screw)

Its particular function on the lathe was to energise the Electromagnetic Brake after the stop button has been hit and the off delay is adjustable and requires no permanent power to relay.... The brake is DC and the control is 110v AC so a fault or loss of AC control would hopefully still allow the braking to function safely.

It oil reservoir works the same way the push button timer switches do normally used on stairwell lighting in flats.

Off delay timer.jpg Modern technology version although can't see this doing the 50yrs service the old one did.
 
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Me only been in the working life 25yrs sometimes seeing these old devices throws a curve ball at me as firstly before you can fault a machine you need to recognise what the hell some off the gear is .... with no wiring plans or any clues on the unit it took a good hour to work out its function and where its role was in the machine ..... once i sourced a modern replacement it took 10mins to replace..... Everydays a school day even for my experienced yrs....

Anybody got any old relics on their shelf that may fall within the nature of this thread then feel free to post them up for us to try and identify.
 
Nice bit of traditional Soviet technology there Dark, what actually failed on it? Most of their industrial stuff seems to go on almost for ever.

While we're on machine tools I'll offer one from our own workshop. It's a 1957 Swiss-made Dixi jig-boring machine driven by its original Ward-Leonard variable voltage DC speed controller. The operator adjusts the speed over a wide range with a small dial on the control panel, it is reversible and has an inching mode. The controller feeds the drive motor with 0-320V 0-65A DC from the motor-generator set which is separate to the machine. The mystery item is part of this system, located inside the electrical cubicle on the machine. It has a laminated steel core with (IIRC) five windings on it, however the answer is not 'transformer'.

Lucien

Control cabinet.jpgPart of speed control.jpgMystery device.jpg
 
Nope, not a choke. There is something a bit choke-ish and a bit transformer-ish about the way it works, yet it is neither a transformer nor a choke.
 
Nice bit of traditional Soviet technology there Dark, what actually failed on it? Most of their industrial stuff seems to go on almost for ever.
50 plus years of a early hard mould plastic plunger eventually wears it away, its possible to probably do a makeshift repair but as its fuctio is braking related its best to replace for sake of £50 ....Electrically still sound.
 
As its multi-tapped windings i assume this is maybe used for selection of speed in some way ...as noted theirs a rectifier on the right, adjustable resistors above .... but without seeing what is used to select speed its a wild guess.

Is the speed selected by a multi position switch or by a pot'

Yep! il say its the old fashio speed control..... just pre-set speeds using the adjustable resistor rods.... ???
 
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The speed is controlled by a pot. AFAIK none of the windings is tapped, they are just five separate windings. The selenium rectifiers are related to the mystery item and they are the only semiconductors in the speed controller.
 
Nope, the power supply transformer is to the right of the DIN terminals. The windings on the mystery device connect to the speed control pot, the main motor, a DC supply, the AC control supply, and one field winding of the cross-field servo-generator on the M-G set via the rectifier.
 
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Thats a cracker bit of kit there. Old gear is cracker. Us, being men, like taking things apart...and seeing what some old things like leccy gear is really interesting, even if it is confusing. A good example is Microwaves.Years ago, built with a nice high voltage transformer in them , made in england,now, replaced by "inverter technology" crap , made in china, and the old microwave will outlive the new one by 30 years. Its interesting to see how things have developed and moved on though, and a small lightweight circuit board has the same capabilities of a heavy, copper wound transformer.
 
Well it's lasted 56 years so far, I've tickled up a few relay and contactor contacts in the last dozen years, changed the brushes and one resistor and that's about all. The rectifiers were replaced in the 1970s. When the machine moved premises a few years ago I did think about putting on a VFD to save having to install the Ward-Leonard set but as it works perfectly it seemed a shame not to use it.

Final clue for the evening - see the pic of the M-G set on which I have labelled the four units. The cross-field machine amplifies the servo demand signal but it's not sensitive enough to give good closed-loop control from the pot output and a small feedback signal. That's where our mystery device comes in.
MG set labelled.jpg
 
Signal amp' or some kind of damper to stabilise speed then if your speed ref is't accurate enough the motor can cycle up and down with speed chasing its self ....
 
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Signal amp

Bingo! Not wild guesses at all... It's a magnetic amplifier. The core is magnetised to half its saturation level by a winding carrying DC. The speed pot sends DC through another winding, the feedback circuit sends DC through a third with opposite polarity, so the steady flux level represents the difference between the two. The degree of saturation controls the power transfer from the AC energising circuit to the rectifier, which produces a DC output to excite the servo-generator, which in turn controls the main generator field and hence the output fed to the spindle motor. 7 hp of stabilised speed control without a thyristor or transistor in sight.

Lucien
DC drive motor.jpgControls.jpg
 
and i trhought it was the missing bell transformer from the ding, no dong thread.
 
Bingo! Not wild guesses at all... It's a magnetic amplifier. The core is magnetised to half its saturation level by a winding carrying DC. The speed pot sends DC through another winding, the feedback circuit sends DC through a third with opposite polarity, so the steady flux level represents the difference between the two. The degree of saturation controls the power transfer from the AC energising circuit to the rectifier, which produces a DC output to excite the servo-generator, which in turn controls the main generator field and hence the output fed to the spindle motor. 7 hp of stabilised speed control without a thyristor or transistor in sight.

Lucien
View attachment 20032View attachment 20033



yeah, just like the hadron collider. lucien, you obviously have no idea what you're doing and i would suggest that you stop now. how are you going to explain your actions when you produce a super-duper massive blackhole that swallows the entire universe??
 

Lucien I know that germanium rectifier looks the part but if it’s in use get rid of it (hide a silicon bridge behind it). I had several burn out, the brown smoke that comes out of them is both toxic and a cacogenic.
PS it tastes foul!
 
DW, ever come across Square D pneumatic timers? Depending how you put them together they were either delay on or delay off.

I may have browsed passed one without really clocking it but cant say ive ever interfered with one in my time.... majority of the machines i work on don't really have any call for delay on or off as i write it into plc software- the delay off timer in my original wasn't too easy to match as it had no/nc contacts on the delay side as well as no/nc instant.
 
Crikey I hope you don't want me to change all the selenium recs here Tony, there's hundreds of the little critters. The ones in the speed controller don't really handle enough power to go up in smoke, only the magamp output, probably just bring the machine to a halt. I don't allow seleniums to be used in situations where there's much likelihood of exposure to the fumes, I agree it's a sensible precaution. Only ever seen one big one go up, on a cinema arc supply, moisture had got into the rec and it failed at power-on.

So, next bit of oddball tat for your perusal, (I could keep this thread going for years). Its name was a trademark.

Lucien
Not your ordinary tumbler switch.jpg
 
Germanium or selenium. Both look the same, both deadly if they burn out. Replace them with a silicon and you need a dropper resistor.

Lucian, I applaud you. Remember there’s a lot of bod’s that haven’t a clue what we are on with.
 
Sorry Tony, not Crabtree. Clue: motors.
 
Is it a manual 2-pole start switch for a single phase motor? When pressed down both poles operate which powers start and run windings, when released one pole disconnects leaving the run winding powered.
 
It sure is Marvo, called the 'Twinob' made by Lundberg/Lektrik. The outer dolly is a momentary spring-loaded type for starting and the inner one an ordinary tumbler switch for running. Got a little 5A version as well with bakelite dollies where one overlaps the other.

Dang, too many experts, puzzles solved too easily, must find odder things...
Two Twinobs.jpg
 

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Mystery Item thread.... What am i?
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