What IS This Thing?????
ฝัง
- เผยแพร่เมื่อ 12 เม.ย. 2023
- Another mysterious artifact from the bins - and some good hints all around to what it is and how it works. Enjoy!
Tim Hunkin's video on solenoids - • SOLENOIDS & RELAYS - T...
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The Secret Life of Machines was one of the finest pieces of television ever made, featuring not only Tim Hunkin but also the sadly missed Rex Garrod. Fran, you and Tim are cut from the same cloth, long life and happiness to you both.
One of the best series I ever saw as a teenager back in the 80's.
I still watch the episodes on TH-cam now and then. Tim is still building crazy machines that entertain the public.
I had every episode of TSOLM on VHS. Might still have them somewhere but they are all on youtube now anyway and enhanced with extra commentary from Tim about the making of the shows. I am so glad he has a yt presence, he doesn't post much but it's still solid gold stuff. Rex was a legend!
Tim is producing a TH-cam series secret life of components, well worth watching.
@@FuquarProductions And he JUST covered solenoids!
I'm at the London science museum right now, having lunch. Will pop down and see his basement display in a minute!
That's a solenoid actuation lock, it's designed to allow movement of an attached linkage, but when AC is applied it will hold the linkage from moving very hard. The shaded pole is telling for this.
I am trying to think how a pole shade helps here. Is it just to maintain magnetic flux during the AC zero crossings?
@@1906Farnsworth Yes, the shading coil on the end basically is at a 90 degree offset from the AC input, so it prevents the solenoid from chattering at 120hz when zero crossing occurs. (maintains the magnetic flux enough to ride through zero crossing.)
@@Ingineerix Thanks!
I think you are spot on.
Exactly right.
I'm a EE 1978, much of my career was in steel mills in need of upgrades, lol. The oldest solenoid controlled system I worked on was a 220Vdc crane that was installed in the mid 1920s. It wasn't substantially different from cranes into the 1990s. It was still in use in 2026 and beyond. Also the mill controls I encountered were late 1940s and up. The sight and sound of size 5 contactors mounted pn the long slate panels was astonishing. Great arcs, gun shot loud armature pickups, it was so much fun. It aldo was fun going through 3 decades of upgrading mill control systems. I got to see wonderful things.
It was for a door lock on a commercial washer or dryer. The knobby shaft bit turned in and off an interock switch. Most of them run on 24 to 28 VAC it is very close to the position you had it in when you made it snap shut. Very similar ones are used for damper controllers for fireplaces and furnaces, but those are usually 120vac. 😁❤🤓
Thanks for the identification
I've never seen anything exactly like this, but in my world of industrial combustion, there are fuel safety shutoff valves that require manual intervention to open but rely on the loss of electricity to close (with spring force). Once the holding power is applied (when the interlock circuit is satisfied), the operator will manually throw a lever to open the valve (closing the coil in this example). The valve will remain open until the interlock circuit is open. Then, the coil will release and the valve will be closed by spring pressure. I'm not saying this is the exact application for this device, but I can envision something similar.
I had a similar thought, but for controlling part of a venting system.
Many years ago I used one of those on a custom automated double width roller door project. I purchased it from a electronic recycling shop in the 80's
and employed it to release a band brake on the motor input to the worm gearbox. It served to stop the motor instantly and also prevent the door from
being rolled up during a power outage. It really used to slam home, mine took full mains voltage and I could hear it from across the street inside my car.
I sold that house after 15 years, and the new owner still has it running to this day, I occasionally adjust and align the guide tracks for him. As you said, it's built to last
virtually forever. Mine had a spring fitted that returned it open and the closing force was amazing, especially as it closed the gap. The band spring in my
application had about ten pounds of closing tension, that solenoid barely noticed it with about half an inch travel.
I've also gathered a few different types over the years, most are linear sliding with a T core, another is a corner pivot like a relay. They are very useful having so much
power for so little complexity.
Tim Hunkin's stuff is great. Glad to see him posting videos again. His Rube Goldberg games and art instalations are over the top.
I wish I was your next door neighbor. So many nice toys to play with. I've seen a similar, but not identical, setup that required a lever to set it to "ON" but disengaged when the power failed.
I do enjoy your shows and quite often see things that I've seen many years before and completely forgotten. 🙂
Man you people are so smart. By you people I mean people that know electronics. It's such a dark art to me, channels like this one inspire me to learn more. Not sure where to start with self study electrical engineering but know that I'm going to have to someday. Thanks Fran!
LEDs, a battery, and a resistor is basically all you need to mess with things and start learning!
Once you understand the basics of on/off, you can look at circuit logic and build an understanding of how on/off turns into what computers do. From there, you just gotta start coming up with ideas you can do and then trying them out (and breaking many things along the way).
Don't play with wall power until you're comfortable. Most hobby electronics are 5v, which you can touch with your hand without even really feeling it. Micro USB outputs at 5v, so that's what's common for power.
And never play with high voltage transformers unless you have a death-wish.
The beauty of AC solenoid type devices as opposed to DC is that they don't tend to get self magnetised over time and start to stick.
You should take a look inside an Electro-Mechnical Pinball machine - they are amazing machines
Oh my goodness. I would be afraid of that. Glad you aren't, Fran. That screen looks so cool!
Fran, I have an early automatic washing machine that has a very similar unit in it to activate the brakes. 240 volts AC. The machine is over 40 years old and still does a couple of loads a week. It is a Fisher and Paykel 380. Almost bullet proof. The timer in it is a work of art, like a sandwich of switches to trigger each stage, had to rebuild it from parts and succeeded after 2 tries. That was about 10 years ago.
Electron compressor was ruled out immediately, due to it appearing to be some kind of solenoid. The light of brilliance exceeding 4 to 7 watts of incandescence shone upon me as I read the wise and informed answers of Ingineerix and Christopher Leubner and others, who all have more than a clue. Thank you Fran, that was fun.
AC solenoids are more powerful that DC solenoids. This one actuates a rotary lever which will give it a greater throw than you could achieve with just something attached directly to the core.
So... I'm thinking that they needed to move something relatively quickly with a longer throw than they could achieve with a DC solenoid, and faster than they could achieve with a pneumatic or motorised actuator. Possibilities might be: to open a very high voltage switch remotely or as an actuator on a pneumatic valve controller where they need to time it accurately.
The biggest Achilles heel of AC solenoids is that if the mechanism jammed and the core got stuck in the out-of-coil position then the coil could burn out very easily.
Tim Hunkin is a "must watch" for all of us. Highly recommended. He has remastered all of his old TV shows so we can now watch them in higher definition that ever before, plus his current life of components videos are extremely useful as he touches on all the most critical things you need to know about various components.
I could also imagine that it is locking mechanism which keeps something locked when an AC voltage is present and that a spring attached to the lever unlocks that something. After the AC is restored the contraption can be set manual to the locked state again. So I think it is a safety mechanism for a power fail.
Seems plausible. That would account for the two different actuator outputs.
Fran, Most of the solenoids (for relays) I have used are AC - from my kit-built electric car charging station (EVSE) to the my ca.1950's low-voltage-AC doorbell mounted next to my front door. How do they work? I know that they hum a variable amount - sometimes annoyingly loud, sometimes almost quiet. So isn't this just a solenoid for actuating that bell crank for a mechanical device?
I have seen something similar at an old powerplant I was doing work at, On high humidity days I would see a similar switch being used instead of manual switches to engage / disengage high voltage connections.
I was doing HazMat cleanup at a plastic plant (mercury spill) and had the opportunity to go in and behind the cases and panels.
Oh! A ker-chunk device :) I have a time clock in my queue right now that has a linear version of such a coil for the "printing". I bet the noise would have been a very satisfying, confirming "I just done my work" signal for the user. Would be interesting where this was used. Vending machine maybe? Limitless possibilities!
A lot of older motor controllers and such use AC 'contactors' of one form or another (although usually the contacts are integral to the device. So this could be for some mechanical movement such as applying a brake to something, or releasing something similar). As you say, the shading coil maintains the 'pull' as the current reverses. The current in the coil is out of phase from the induced voltage and can be as much as 90 degrees lagging. It is an older technology, back when a simple shading coil was easier than a bulky silicon rectifier of that era. As the flux in the unshaded path rises, the current in the shading coil opposes the rising flux within the coil area and later when the flux is declining, the shading coil current sustains it. So you have two parts of the pole face with flux inside the coil and outside the coil peaking at different times.
It's a common failure mode that the shading coil would come unglued and fall out. Then when you turn the system on the contactor still pulls in just fine, but 'buzzes' loudly because of the drop in force while zero-crossing. More than once we made repairs with a bit of epoxy to put the coil back in place until we could get a proper replacement.
Love Tim's content and remember watching the TV series The Secret Life Of in the UK when I was a child.🔧👍
I believe they were the shading mechanism actuators for heavy in window blinds during the nuke tests in Nevada. The blinds louvers were lead coated ...
Perhaps Fran should check it with a Geiger counter.
This was exactly the electro-mechanical geekery I needed before bed tonight. Thanks!
This type of thing was used a lot in older machinery to effect something like a shunt-trip main power breaker in large control panels before shunt trip breakers became more integral.
Basically, the 'arm' of the device was connected to the user operated handle for the main disconnect for the machine that was a switch rated breaker. The flatted shaft was connected to a linkage that had a slotted plate fitted over the breaker 'handle' mounted in the panel or separate disconnect switch, and the winding was powered by one or more safety sensor circuits designed to shut the whole machine down if some in something critical went sideways.
I've seen something similar to this controlling damper's on a wood furnace. A neat solution to control things mechanicaly.
@Fran Blanche , Go down the rabbit hole of postwar Lionel trains. DC sensitive relays controlled horns and whistles from the transformer, while vibrating devices introduced all kinds of linear and rotational action to Lionel accessories, or the rotating aircraft beacon which had a housing that rotated from the heat of the bulb inside of it. Lionel's engineering department in those days was downright Arthurian!
Did it here - th-cam.com/video/yP89xhVLK9o/w-d-xo.html
Unusual type of solenoid must of had a return spring and maybe a manual override on the flatter spindle side for a manual lever? Possibly for the nuclear industry for some sort of vent opening , but I don't know I'm a motor engineer retired ,love this stuff keep up the great work Fran
Thanks for brightening my day, Fran! I really needed a pick-me-up! ☺️☮️😎🤘🌈
SLAM!
I was thinking in lines of sensing the angular position, with variable inductance depending on the air gap width.
The shading coil is the givaway.
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
@@8546Ken yes, Fran already mentioned it.
Glad you had this and produced the video because I also appreciate the efforts that the engineers went to here. I remember my brother had a solenoid about the same size, but simple linear stroke of about 1 1/4 inches. Had a spring to pop it open a bit after release. I don't know what it was from but it made an impression on me. That was 40 or so years ago when he first got it, and it kicked around in a box of transformers for years because coil.
When you first hinged it open I though "uh oh... Pinch potential!"
My Dad worked in a melamine plate manufacturing plant (1970s).
He was always bringing home little doodad thingies and gizzmos.
At 10, my favorite was a brick size chunk of plastic (bakelite)
with some wire connectors.
He call it a Flip-Flop.
10 years later in a Computer Science course,
I discovered the Integrated Circuit version of that brick,
and the circle was closed.
-- 7.24.2023
Rotary solenoid actuator (partial turn).
Btw I have several AC linear solenoids with laminated armatures and coil cores. They are/were not uncommon.
You will find them in pre solid state motor starter relays
There is one very similar in my washing machine. It shifts the water pump in at the appropriate time.
Most I've seen in washing machines lock or unlock the drum between wash and spin cycles👍
Chris Ingle -Dang- how old is that unit? And is it a speed queen?
Fran I believe this works as a control similar to a saturable reactor, but using mechanics to control the current allowed allowed to pas through. This was my first thought… 😊
A saturable reactor (i.e. form of mag-amp) wouldn't need a shading coil. That thing is meant to actuate some mechanical thing using just AC power.
A saturable reactor would have a primary and secondary.
Saturable reactors are a completely different beast.
@@srtamplification There is a one turn secondary there?
Looks like a solenoid to me. Nice to know about shading coil. Thanks for finding an a fun bit of obscure tech to show us. I did wonder if if it was from some kind machine interlock or door lock system with so much travel in the arm.
You always have the coolest stuff .
First blush, it looks like a solenoid. 🤔
Had a large similarw version of one of these years and years ago from a huge dictation machine and was used as a solenoid to switch a mechanical part of some sort. I was particularly amazed at the back emf it generated by the sparks when I disconnected the ac from the thing.
I wonder how the return spring would be angled, although it might have used springs in both directions.
It's always a particular kind of thrill to get a device operating and wondering what it might have been used for.
Even better when I realize "I have a use for this thing!"
Great stuff Fran!
Actuators similar to that one were (and are still) used to disengage mechanical brake assemblies used on hoists. Larger and older 20 ton + cranes would use an actuator such as that attached to the backing plate of a mechanical drum-type brake assembly connected to the hoist drum or gearbox directly. The keyed shaft end would turn a cam assembly inside the brake drum usually only about 15 degrees or so to retract the spring held brakes inside usually kept at about a millimeter or two away from the drum.. The opposite end actuator arm would be connected to an outside spring anchored to an opposing end to help retract the solenoid (brake actuator). Sometimes a limit switch would be installed to confirm disengagement. These coils usually ran at 120 volts AC. Understand that for safety, hoist brakes are mechanically held on and require an electrical "disengaging" mechanism in order to allow the hoist to then operate. The reason the coil needs to be so large is to create sufficient force to overcome the spring tension inside the drum brake assembly.
Decades ago while a kid in school one of my neighbors tossed out their 1969 era washing machine.
I opened the back cover and removed the drive motor to make a polisher.
There was a solenoid the same size but vertical pole for I believe shifting it's cycle.
It was designed for 120vac and a very strong pull just not intended for being applied for more than it's cycle time afaik.
This design was discontinued later and the only magnetic solenoids were much smaller and for tub fill and tub empty, valve and coil a one piece assembly.
This was more of a "gear shift" than for water control.
Contactors use the same base.
My first thought was that it was a permeability-tuned inductor, which could be used to tune an oscillator for radio (or otherwise). I bet it would still work as one, and it probably has a huge range with such a large core...
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
I figured out what this was just by seeing the preview. It's the operating mechanism for an electric door strike. When unenergised, the door's "strike" is in the normal position and if the door is locked, it cannot be opened. When the coil is energised, it pulls the arm which then disengages the strike. Pulling on the door then allows the bolt to push the strike out of the way, effectively unlocking the door without having to unlock the bolt. Once the coil is unenergised again, the arm extends under spring tension which once again engages the strike, preventing it from moving which again allows the door to latch into the locked condition.
It appears to be some type of actuator. Possibly emitting an aroma of old "shellac" from the coating on what looks like a coil, most likely for electromagnetic field generation, and/or a transformer, as there appears to be two "tap points".
For some, it could be an extremely useful paperweight and conversation piece, even to the point of warranting an interesting video to be created and published that presents it to the public.
:) _John_
Ah yes, the 'pungent aroma' of burning shellac. Smelled that many a time. Also would hear the loud BUZZ of when the shading coil would fall out and need to be replaced.
My guess: a 'door buzzer' - a solenoid that unlocks a door remotely.
You'd be an amazing teacher. I'm certainly learning a little something with each video like this. I worked in HVAC controls for years and would see similar devices in some older machinery.
Before reading all the other comments my mind went to controlling a door. As long as power was applied it would be locked shut, but when you cut power it would allow the door to open and if you fully open the door it will remain open but if the door is closed slightly the magnetic field would pull the door closed. After watching the video I think the orientation you were using it is correct, there was something on the armeteur and when power was lost it would fall open, then once power was regained an operator could come by and reset it when ready.
I think some other have mentioned below, but I'd love to see how much holding power it has when energized. Could be an electromechanical lock or interlock.
Have seen one burn out, 208 volt coil used to hold a shorting interlock bar on the 14 kv supply on an RCA TV transmitter. It was linear though, with the core being limited to about an inch of travel so never entirely out of the coil. Very simple gravity operated part of the safety interlock system, powered from a knife switch with a three foot handle that was across the door entering the transmitter.
I like to see you having fun.
i found a similiar mechanism in a gas furnace starter. the core had a magnet wedged into it to allways stay in saturation and a mechanism that lifted one of the core to break up the flux causing a change in magnetic field and a spark on the coil.
AC solenoids tend to buzz at harmonics of line frequency when energized. I suspect the shading coil is to keep the poles in contact during the zero crossing, allowing silent operation.
My first thought was variable core, not actuator. fascinating
I’ve read that the constant current power supply that dimmed airport lights (pre- solid state ) used an adjustable iron core. However I have never seen one. I believe it’s an adjustable impedance coil meant for handling higher voltage and power.
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
@@8546Ken Yeah thats why I said first thought, the reality was much stranger
I think it is a variable inductor, the crank and pins for springs and mechanical input control, perhaps for an antique phase-lock system.
Could it be part of a speed governor for an alternator set, to keep the frequency correct.
I was thinking it's either movement limited to prevent you from completely exiting the core, or it was designed in a way that if AC was applied to the coil and you flipped the lever it would catch and hold the lever in. Basically if you armed the system it would only allow you to mechanically activate it but not mechanically de-activate it.
Solenoid coils don’t require DC. As you just demonstrated. A shading coil is not required for it to work. Surely you have encountered relays with AC coils before.
AC powered solenoids are used in door chimes and old washing machines.
It looks like some sort of interlock solenoid, I’m guessing it is manually closed and then the solenoid is used to hold it closed along with interlock switches to allow a machine to operate.
Could it be part of a breaker system, no voltage reset? A spring and main breaker attached to the lever. The smaller end of the shaft with the flat, connected to an indicator pointer to show state?
That's what I think, an actuator for a no voltage switch. There would be a manual lever to close a set of spring loaded contacts that switch power to a motor or something like that and also to the coil. When the switch is manually closed the coil is energized through the contacts and holds the switch closed but if the power i interrupted the coil will release and the spring will open the contacts and manual reset is required to restart the machinery. Very important on things like circular saws, conveyors etc. as you don't want them to restart unexpectedly by themselves after a power outage when someone might be in harm's way. The shading coil would be there to prevent buzzing by maintaining a magnetic field at zero crossing.
Big Clive featured a similar device a while ago, though his was much smaller.
It is a speed governor for gasoline or diesel powered generators. The control circuit varies the voltage on the coil to cause the arm to move the throttle thereby holding the generator relatively constant at the desired frequency.
These devices are still produced on mass today, they do an excellent job for what they are designed. The actuator works against a spring so in the fully closed position would be full throttle on the generator. Under normal operation with engine running under load, the core "floats". The control circuit can be set to adjust the speed of response to load as well as how much overshoot it gives.
I love this device - where can I buy one of these?
People are positing that it's an actuator but what if it's a variable inductor? That is, designed so that a mechanism can vary the inductance of a single coil? And the shaft with the flat on it might be for a control knob, but it could also be attached to the needle of an indicator dial?
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
In the era of it's date stamp there would have been many machines to use solenoids, from building services machinery to one armed bandits in casinos. For a low duty cycle function that particular one could even be mains 110v operated so that it had significant force to apply to a mechanism to move a significant load.
It could also be an electromagnet with a mechanical release feature (the lever). The lifting surface would be the bottom of the coil. Of coarse the release could also be accomplished by just cutting off the current to the coil.
You find the same principle of shaded pole in ordinary AC contactors (and AC relays). There is a characteristic change in the inductance during the operation. In open state the inductance is ver low and there is a high inrush current. But when the contactor is closed, the inductance is much higher and the holding AC power requirement is a small fraction of the start of movement time current. I have measured the change of he inductance, as well as he current some time in the past. Now I did not find any contactors in my home stock. I did find a 24 V AC relay. It reads 205 mH (at 120 Hz) open. I need to battle the cover removal, before I can measure the closed state inductance. Turned out to be only 284 mH. I expected a higher ratio, but so be it.
The contactor in every central heat pump or air conditioner is an ac solenoid that is energized by 24vac through the thermostat. It closes the contact and sends 240 vac to the compressor.
Maybe it came from an old pinball machine which loaded the steel ball in the shoot where you pull the spring lever back to launch it.
That's where my thoughts were going... flipper solenoid?
@@jondhuse1549 yeah that would have made a great flipper solenoid also.
Not seen anything like that before. At first glance I thought it was similar to something I saw on one of Shango066 videos a while back. He was working on one of his old tv sets and they were using a transformer that was physically adjustable in order to adjust the output, I think it was used for adjusting the focus on the picture tube. But that was very different, the core only moved a couple of millimetres at most, I think there was a rotary control on the back of the set that physically moved the core of the transformer in or out a fraction. But this thing of yours is obviously very different.
I thought it might be some sort of tuning device for radio (or radar). But it could also be some kind of speed controller. I still think it's some kind of frequency adjuster. Might even be involved in the frequency of the AC current itself
That’s an electromagnetic actuator from a circum-snip 5000.
It became very popular between 1968-1989 until a terrible unforeseen accident all but removed it from the consumer market and history.
My first thought when you showed both sides was not one of the things you mentioned.
It would be interesting to see what kind of force is exerted - maybe with a spring balance/spring scale - to give an idea of the weight of what might be moved by the arm.
My first thought was for a tuneable choke/inductor.
The lever is long enough to allow for small movements of the core into the coil. As the core moves, the flux increases and the AC is reduced.
I don’t know if such a device exists.
Thanks for that but of information about shading coils, I've encountered contactors that chatter and on occasions the reason was a cracked shading coil, I repaired many but didn't know why , but now I do😂
This is the kind of content i like, get something from your storage, and explore! More of this please!
As it probably changes inductance with position, with a series of caps we could make a tuner and the arm drive a needle on a string drive.
reminds me of the electronic door locks used by Crichton in the Jurassic Park books, Grant is described hearing the solenoid clicking, followed by the door opening.
It looks very much like the release device on lenor elec dc breakers. They are still used in europe for train and hydropower, carrying thousands of amps. The design is from the 60 or so, still in use!
that is a "buzz you in" style of door lock, used for many years in medium to high security areas like bank employee doors, high end office doors, and in anywhere the public access needed to be highly controlled but easily run by any employee
Old electromechanical devices such as washing machines only had mains power available, no low voltage DC in sight, hence solenoids like this were commonly used.
My thoughts would be that it is an interlock that keeps the movable core pulled in while power is applied, and this whatever control it’s attached to from being moved or door from being opened. Since it has such a large range of motion, one would not expect it to pull in on its own, but stay closed when powered.
My guess as to where this would be used would be in electrical substations for automatic disconnects for power issues such as downed lines. And may also be the actuator for a large contactor for high power load, and manufactured in that way so as to make it serviceable. With the flat part on the opposing end of the shaft being for a microswitch to indicate its position.
It would be much better than a simple solenoid if you wanted a more even torque over a larger range. A very clever device!!
My guess is some form of industrial valve control..air, liquid fuel or gas....
At my last job, the boiler had similar gizmos, just somewhat larger.
The Secret Life of Machines! ( and Components).... excellent show! They should be shown in schools.
Might be the kind of thing you would see on a door latch, like older apartments where you "buzz" somebody in. Perhaps the buzzer and the latch using the same AC power?
I guess it is a locking-mechanism.
And - at that time - it was easier to just use AC instead of going to the difficulties to use expensive (plate-) diodes to make DC for the current needed.
I think the shading coil it's more for keeping it closed than for closing it in the first place.
Try 115 V ac. We used many that overcame rather strong springs. After many cycles, pole shaders can crack and fail. A little solder and they behave for months or years longer. Boilers may have used them for vents and gas valves etc. eons ago.Boilers have used torque motors for decades.
A very heavy duty solenoid of some description?
Possible redundant elevator door lock designed for decades of reliable open/close position, etc...
Perhaps it was used as angular position sensor, rather than an actuator. It could translate changes of the arms position into a change in the inductive properties of the coil.
For that kind of sensing application you want a solid carbon core, not laminated steel.
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
I have seen many of those. Factory machines use them all the time. Unidirectional mechanical/electric actuator.
It looks very much like a stepping solenoid used on an Edmiston Hydraulic Sawmill on the set works that moves the log in proportion to the thickness of the board to be cut
The line cut the pole surface keeps residual magnetism from holding the solenoid closed against spring tension when the voltage is removed.
Its an actuation solenoid. A similar solenoid operated an agitator drive clutch mechanism on the old Hoover 'Keymatic' washing machines (late '50's early '60's).
Variable inductor. I've seen different methods of achieving this. Did you take inductance measurements between open and closed.
So because of ELI the ICE man - it would make a pretty good motor speed controller, huh?!
If it were used as a variable inductor, it wouldn't need the shading coil. It's obviously an actuator.
Fire door closer? Held open until interruption of power either by failure or by sprinkler system. This application would account for the heavy-duty, fail-safe style of the thing.
Looks like solenoid but could be an inductance adjuster for a welder. I've seen something similar in 1940s xray machine I took apart a while ago
It reminds me of an old string chopper on Tie-Master tobacco stringer (it was like a swing arm guillotine
What inductance does it have when open and closed?
I'm thinking the term might be "actuator." It's a lever operated with a solenoid, and I can think of numerous applications where something like that could be used.
made to work like... forever - pride in the product, no planned obsolescence