Ferroresonant AC mains voltage regulator (BLACK MAGIC BOX)

[@j--xe3ke]

Never give this treasure away! In these days nobody would build such a robust device with 10kg iron

[@annaplojharova1400]

There would be plenty of shops willing to make it for you. Once you will be willing to pay that nearly 1000 Euro for just a 300VA AC regulator. So it is not true nobody would be willing to make it. The real truth is, nobody is willing to pay for it these days.

[@mernok2001]

@@annaplojharova1400 Yes,thats true.My electronics teacher said that he wanted to buy a more expensive water pump with porper motor and windingd,but the salesman said there are only cheap ones. Then he said that the salesman didnt tell him but he thought that only he would be stupid enough to buy a more expensive pump.

[@zarkoujdur9424]

I agree, there is no UPS which can replace this gem, AFAIK...

[@youkofoxy]

unless under contract or DIY.

[@WizardTim]

Never properly knew how those things worked even after reading the Wikipedia article about them, great video explains it well! Loved the LED rolling shutter trick as well.

[@smartups1]

Which article . I want to read.

[@WizardTim]

@@smartups1 en.wikipedia.org/wiki/Voltage_regulator#Constant-voltage_transformer

[@DoctorCalabria]

Thumbs up for the LED trick!

[@BRUXXUS]

This kind of blew my mind throughout the whole video. At first, because I had no idea how this was even possible. Second, because you did such a good job explaining HOW it works so, by the end, I understood! Is this what people call elegant engineering? I definitely think so.

[@d1s1ntegrator56]

When I was a kid, I tore down quite a few of these devices. My grandpa and other relatives used them in 60s-70s when there weren't any electrical grid, just some local town generators with awfully bad frequency and voltage fluctuations (could see light bulb blinking with bare eyes). He said, that TV would just fry without one of these, always wondered, how do they work...

[@laszu7137]

Even then very risky. A too high change in frequency could make this kind of circuit produce spicy voltages over 300 volts.

[@d1s1ntegrator56]

@@laszu7137 As far as I know, no TVs were fried, so I guess it was alright.

[@arthurmead5341]

What country was that?

[@d1s1ntegrator56]

@@arthurmead5341 Lithuania

[@j1952d]

Many thanks for the explanation. When I started work (in about 1975), we had some problems with unstable mains supplies. My (old school) boss said "we should use a ferroresonant regulator". I had no idea what he was talking about, but I nodded. They were too expensive, and "normal" power supplies were improving, so we never got round to using an FR regulator. I didn't get round to studying what it was or how it worked at the time, but I've often wondered. Thanks again.

[@mernok2001]

Which country?

[@j1952d]

@@mernok2001 UK

[@Kitsaplorax]

I own several modern iterations of this device, following a local power line accident that shorted out some electronics in my house. These devices are so much better than anything with a MOV design. They are expensive, but are military specification and I don't need to worry about them burning out without warning.

[@peterjohnston8116]

In 1962 I worked in a mobile telecommunications repair truck. It was fitted with a ferroresonate AC regulator as the power source was usually a 240 V AC mobile generator. The unit was made in England and worked well without any active components.

[@LMB222]

Do they keep the frequency well? Some other comment claims they used it for a TV, but older TVs used then 50Hz network frequency as the image synchronisation frequency. A diesel generator, with a variable frequency would cause the TV screen to "float" up or down.

[@hooya27]

I worked at a UPS factory that made ferroresonant voltage regulated equipment. Interestingly, input power could miss several cycles, and the device output would remain. This was possible because of how much energy is stored in the electric and magnetic fields of the regulator.

[@Conservator.]

To the donor: Thank you! 🙏 I really enjoy DGW video’s and your donation made this one possible. It’s amazing that the regulator is still in such an excellent condition and that you included the documents. Vielen Dank von ganzem Herzen!

[@JamesBrown-ux9ds]

Wir stimmen zu - und haben auch so etwas wie gedacht wie 'und das war noch deutsche Wertarbeit - Kondensatoren aus 1264, und noch kein bisschen alt oder müde, Funktion immer noch perfekt''

[@nosaltiesandrooshere7488]

👍 Danke fürs Hochladen! 👍 Thanks for uploading! 👍 Very good and beautiful, thank you! 👍 Sehr gut und schön, danke!

[@victordesanderobledo4522]

It looks like black magic but it really is german engineering. They're easy to mistake. ;)

[@transkryption]

Im not so sure, the SS had all of that weird occult stuff going on! kzbin.info/www/bejne/b2fVkKGsoKhmZrs

[@MonadSentinel]

@@transkryption then the US Took Most of that stuff and founded nasa

[@mobapc4095]

YA he is Czech.. and he is best FULLBRIDGE RECTIFIER troll with freeky engrish..

[@mcflapper7591]

One of the most interesting topics in years on the entire youtube thing. Thank you!

[@antibrevity]

This thing is amazing! Thanks to the donor and to you for sharing it with us and explaining how it uses seemingly simple I-C resonance(s) to accomplish a complex task that today would *require* active components to be commercially viable. Anything built with large inductors is obviously from the distant past as no one can afford such things today. Circuits today are built around active components and R-C filters and even then the capacitors are so cheap that they sometimes blow their guts upon first power-up :(. Large inductors were heavy and required a lot of metal resources, but they were more robust than the humans building and using them. It's likely that every human associated with this product in 1965 is now dead. The product outlived its application, however, and it will outlive all of us unless someone steals it for copper scrap. While products without useful purpose should be recycled into things that we now need, it would be a shame for something so amazing to wind up as copper-clad aluminum in some dodgy Chinese electronic product that will be thrown into a landfill 6 weeks after purchase :(. Can't wait to see it on the scope.

[@Matt47247523457]

ohhh, I have to remember the rolling shutter trick. That was clever

[@dwaynezilla]

This is great. I've been wondering if such a thing was possible for a few years. Not enough to look it up, mind you. I figured it wasn't really a thing, mostly because, "apparently," no one made them. I thought maybe the range wasn't useful enough. But no, this one looks decently useful. Instead it's probably a matter of the cost of all that metal, and AC voltage not being important in 99% of applications, especially in 1965. Then later when precise voltages were required, we already had a bunch of solid state stuff to build better/cheaper/more-accurate designs. What a neat find, and so glad this was sent to you and you tore it down for us!

[@pdrg]

I would love a demonstration of why gap Vs no-gap cores is important/makes a difference - for instance why usb power supply topologies require the gap, and maybe some nice graphing like you have done here, just remove some mystery! Thanks for a quality video.

[@davidpolacek4902]

I too

[@wdujsub7902]

From what I read when you are using a flyback topology then all the energy that is supplied to the output is in the case of the transformer stored in its core as a magnetic field which is potential energy. That means that the core material for higher efficiency should be able to saturate at a higher value of magnetic flux than in the case of a typical forward transformer and that is achieved by adding an air gap in the core, because the air is harder to saturate and so the overall path of the magnetic flux in the iron core can achieve higher magnetic flux values without the inductance dropping. Please correct me if I am wrong. And yes I would love that too!

[@Basement-Science]

When you need a high saturation threshold, using a core with air gap is just a simpler, cheaper way to get it. You could use a much thicker core instead. Another downside of having an air gap is that you need more windings for the same inductance, meaning you get more copper losses.

[@analoghardwaretops3976]

And also more fascinating is "THE SWINGING CHOKE" circuit behaviour is when there is a variable air gap... 1) one limb as normal..& the other limb tapering from one edge to its opposite..... ....OR... 2) one limb with conical taper..fom out to centre..., such are more useful in stable voltage conditions ..but for dynamically varying loads that require good load regulation...

[@Miata822]

Beautiful engineering. Inductors have magical properties. I hope you can touch on the math in the next episode.

[@hernancoronel]

DIODE: You are AWESOME! Glad you didn’t tear down such a jewel! Thank you, thank you, thank you!

[@pirelli77]

I am also surprised how little electricity is inside, it is almost nothing and still more precise than many things you can buy today. thanks DGW and thanks to the nice gentlemen from germany for this interesting donation!!!! And a big KISS to your sweet CAT 💋 ☺️

[@jeroenjeroen]

Great video again, true understanding of basic electronics, almost a forgotten art!

[@PeterMilanovski]

Bloody hell, now all the audiophiles are going to get out there and buy all remaining stock of these things so that they have regulated voltage for their turntables!!!

[@analoghardwaretops3976]

Quick ..somebody make a waveform " template " 😁😁 for them to buy.. 😀😀start a new business..for more money flowing in..

[@laharl2k]

Its probably cheaper to make a electronic one instead of using 20 pounds of copper and iron.

[@sleepwalkerbg1]

Audiophiles belong to all other "philes"... The psychiatric ward ;)

[@michaelfisher9671]

This is one of your only videos where I haven’t felt like I was able to keep up. I think I need more background with resonance and inductance

[@LMB222]

Refresh your comes numbers. Otherwise it's difficult

[@BRUXXUS]

I was just on the edge of being able to understand it, but I think he did a great job explaining it. Having a grasp on how inductors, chokes, and magnetic field saturation work helped, I think.

[@Conservator.]

Good to see there are at least 74 ‘early viewers’! We really like to support your videooo’s … 😉

[@davidprazak1599]

Bloody hell that`s amazing... Nice vintage regulator. And in 18:50 that is genial idea, I will use this. Nice video as always

[@therealjammit]

I have a mains isolation transformer that also includes voltage regulation. It also has the "special" transformer with a bank of AC capacitors. The voltage regulation is unnecessary for what I needed, but it was cheap from a ham radio meet.

[@anoimo9013]

very good information. there's not much information over on ferrroresonant regulators. espacially on double core ones

[@xffx-sk1dv]

LED trick was brilliant !!

[@slobodanjovanovic8166]

This is excellent explanation how this thing works, good job!

[@user-qf6yt3id3w]

What a fascinating device. I like the way the compensation winding is like adding an extra term to a Taylor series. Whoever invented this technique was a God-tier engineer.

[@Hasitier]

Very interesting to watch. I did not know that such devices existed and how they work. Thanks.

[@andymouse]

Wow, I kinda get it, great explanation and smart use of your camera to demo the phase, black magic indeed !....cheers.

[@balas3037]

Very clever technique to figure out phase dots from led and rolling shutter!!!

[@1pcfred]

I like how it is wired. It is a very neat job.

[@Mladjasmilic]

My great grandparents had one of these voltage stabilisators for TV. Line was single phase AC, about 2km from local transformer. Trouble was, neighbor had welder and my father told me that, when he was a child, whenever he welded lights would flash. They used it for radio and TV, which back then were using vacuum tubes and needed stable voltage. Using stabilisators, it could iron out the voltage. Otherwise, TV would flash and turn off. In the '90 line was upgraded, 3 phase AC and transformer was 80m from home. But old great grandparents were still using stabilisators. Their black and white TV kept working until digitalisation to DVB-T2 in 2015.

[@mernok2001]

What country?

[@Mladjasmilic]

@@mernok2001 Jugoslavija

[@fethilakhdari1078]

Great Video, clear, concise, accurate and just good all around. Please keep them coming. Cheers

[@limrc1]

Brings back good memories and I'm impressed that the capacitors still work. Here in the USA, Sola is the champion maker of CVT and their winding configuration is a bit different. The resonating LC tank circuit is the same principle as IF (Intermediate Frequency) used in old radios (XL = Xc). Shunt regulators are very inefficient. Looking forward to the oscilloscope readings. Won't be surprised if there are distortions. Please more USB chargers videos and test Apple products. Thank you and I really enjoy your videos. Keep them coming and more often!!

[@gordonwedman3179]

I have a couple of Sola CVTs salvaged from discarded scientific equipment. Much smaller than what Diode has. Don't recall the specs but I was quite amazed at the degree of regulation they achieve.

[@snakezdewiggle6084]

Always enjoy your vids, many thanks.

[@MissNorington]

Need more LED rolling shutter tricks in the future, since transformer's functions are difficult to understand without destroying them. Great video!

[@DolezalPetr]

Solidní předvaděč spojitosti, hustý, něco takovýho bych nechtěl vypočítávat

[@fluffyblue4006]

Very very interesting. Thanks for analyzing it, and kudos for the nice led/shutter phase detection trick. Also a big thank you to the donor. I can imagine these things in big, in use by power companies, for regulating line voltage.

[@msansjr]

What I really wanna see is the next episode! The oscilloscope is there to increase the tension on the hanging end...

[@kevinwelsch]

Das Teil gefällt mir. Super Technik!

[@MyProjectBoxChannel]

Analogue stuff is totally awesome. So much cool stuff happening with a couple of "passive components"

[@m3sca1]

very elegant design! great trick finding the windings with a LEDs strobing under frame rate...clever!

[@aicisha]

Wow man, you got some sick electronics knowledge! Also the led shutter trick was out of the box!

[@МихаилЦымбал-д9м]

Magnetic/Induction based devices from past are all looks like some black magic. There's even some sort equivalent of transistor for AC, based on saturable inductor (or as it called "saturable reactor"): just add another winding apply DC to it so inductor go into saturation, inductance drops...and so does AC impedance.

[@josephe3697]

Would that be a magnetic amplifier?

[@MaleLion.]

What you mean is a transductor. You'll find them in old color tvs.

[@josephe3697]

en.wikipedia.org/wiki/Magnetic_amplifier

[@MeriaDuck]

This magical device is stunning! Thanks DiodeGoneWild an donor! Wonder how (in)efficient it is. Cliffhanger! Do we get to see the efficiency in the next video? Looking forward to the scope images.

[@robson6285]

When nothing gets very hot there is not much of losses, and when not overloading (what would be a pity with such beautyfull and well kept device) there are probably only very slight distortions visible from the sinusses that each point will show. (At least that's what i think, but that's only after i saw his explaination because without i didn't understand a bit of it. Its a remarkable video about an even remarkable device and i cannot think of anyone not glued to the screen in this vid. (Only i mis the many times he use the word "basically" like he used to do in his older vids. Until some idiot (like me) giggled about it in an ever regretted stupid kidding-comment!(and you see it yourself, my english is so much worse than his (and the same for my knowledge and understanding of electronics!))

[@listerdave1240]

"Any sufficiently simple technology is indistinguishable from black magic" - Carter C. Lark

[@copernicofelinis]

Ok, everybody commenting the electric gizmo, but what about that 1965 piece of paper at 4:28 that looks printed yesterday?

[@rilosvideos877]

This is really a clever invention back then and also a very smart analysis of its function by DGW :-) Today they would use a lot of semiconductions and Microprocessors to achieve this with much smaller lifetime i guess! This technique is 70 years old and works still perfectly!

[@smokyatgroups]

A beautiful well researched description, thank you so much!

[@superciliousdude]

That was fascinating. Can you do a follow-up video of what the waveforms look like when the input is not a clean sine wave? What happens when you feed it a stepped square-ish wave from a H-Bridge or something like that?

[@marka1986]

The US also had this. I believe the most prominent brand was SOLA. Zenith used this setup in their tvs in the 70s

[@Langendimi555]

Nice trick with the led's!!

[@fullmetaljacket7]

18:50 And that was insanely cool!

[@RavenLuni]

Awesome - I might try a small scale model of one of these as a fun project

[@johnconrad5487]

Thanks for the explanation. Very good.

[@mariogudelj5815]

I remember that every TV was plugged into one of these in 80’s where I lived.

[@zoltandiveki5233]

Indeed, I recall seeing this device in my grandparents house. It was also in the 80s and they used it to protect their TV. The mains voltage used to fluctuate wildly there (small village in Southern Hungary)

[@annaplojharova1400]

I think the saturation inductor has an air gap too, just a bit thinner. With air gap you get sharper saturation effects, of course with lower initial inductance.... By the way the art of magnetic amplifiers is not completely forgotten. In a typical ATX computer power supply box you find an amplifier, which has only 2 terminals. Yes, an amplifier, with an input and output ports, but just two terminals overall. It is a current controlled PWM switch to regulate the 3.3V branch. Its construction? A toroid shaped core (the core is a coil of a thin strip of some metal, encased in a black plastic resin) with about dozen turns of a thick wire.

[@douro20]

Is that a Czechoslovakian variac? I have a very old ferroresonant inverter which was built back in the early '50s. It runs on 12V and can source up to 300 watts at 115VAC. It uses a mechanical chopper to drive the ferroresonant transformer. It was designed for powering radios and TV receivers.

[@HomelabExtreme]

This is absolutely amazing, wow... I can't help to wonder why this hasn't been more widespread, i have never seen a regulated power supply like this.

[@marc-andreservant201]

There's also the Soviet version: a variac with a slightly dodgy servo motor connected to a type II controller made of resistors, capacitors and an op-amp. When the voltage changes the servo turns the dial.

[@LMB222]

Lemme guess, there's no secondary safety system to shut the output off when the servo gets stuck too high…

[@TheCarlos206]

Excelent explanation, waiting next video....

[@Stoney3K]

Cool to see you still have the original receipts of that unit, looks like it was used in a photographer's studio -- perhaps to stabilize the output of the studio lamps?

[@Gengh13]

Awesome piece of engineering.

[@robson6285]

Wow... I can only say WoW! I am speachless. That "old" technics is amazing, and also, How o how did you find áll that aspects from the working, how you could find out even the basicworking?!! Some of your video's are really jewels of knowledge gathering for us, but this one is stunning interesting good! Really Wow² !

[@samsmith9764]

Awesome explaination, thanks!

[@stephenstebbing9460]

Bloody long but bloody interesting. Thanks.

[@drdrums1]

I saw "ferroresonant" and my first thought was... sounds like an LC circuit in there. Isn't this basically a controlled shunt reactor? They use devices like these, albeit much, much bigger, in power transmission systems to stabilize line voltage and compensate for parasitic line capacitance.

[@zx8401ztv]

You clever clogs :-D My brain was trickling out of my ears lol.

[@fullmetaljacket7]

This is better than EEvblog.

[@Batmule]

Wow! Great explanation. Thank you!

[@mohinderkaur6671]

Best explanation

[@klassichd10]

Thanks a lot! I knew that this stuff exists and I always asked how an arrangement of "fixed" passives could act as a regulator.

[@DuroLabs85]

Those are some chunky inductors and capacitors and nowadays they can fit 1KW stabilizers in half of that size!

[@5Dale65]

Simple yet ingenious

[@morijitesh5923]

Constont voltage transformer (CVT) Grate video and amazing explain👍👍👍👌👌

[@DiodeGoneWild]

Not sure if this is called CVT. Maybe only the single core ones are called that way...

[@Speeder84XL]

Really interesting! - it must have been quite a lot of work to tweak something like that. Impressive engineering :)

[@LarryKapp1]

How did they ever figure out how to do that in 1965 ? Lots of math and physics smarts ? Or lots of trial and error ? Maybe both of those !

[@slawo1231]

Or maybe they had a lot of steel from scrap tanks

[@HazeAnderson]

1965 people were really stupid therefor ALIEN TECHNOLOGY!

[@analoghardwaretops3976]

Those were the days the Electrical Engineers really did the maths and analytics mentally and on the drawing board... & saturating core inductors etc. was a useful option that was widely used back then.

[@mjouwbuis]

The principle might date from before WWII. It has a high Tesla/Westinghouse/Siemens vibe to it.

[@weinihao3632]

The idea seems to originate from the late 19th early 20th century, when people experimented with the most exotic principles to achieve power amplification. In case you can understand German, there is a long article at the electronics discussion site mikrocontroller.net discussing Transductors (magnetic amplifiers) as shown in the video. www.mikrocontroller.net/topic/der-magnetische-verstaerker

[@harrilumme1875]

Please test the sine wave purity and power factor under different loads. Thanks for very interesting content!

[@tigerelectronics5966]

I recently aquired one of these too! A 1kVA Fiskars unit! Mine is also +/-15% Input, and 220V or 230V. Seems rock solid! I tried testing it with my Variac but my Variac starts humming really loudly! So I don't know if it's good to try on the Variac. I'm scared it might damage my Variac. I'm going to install it in my room, to keep my older radios happy!

[@child_of_god_]

I have never knew this kind of thing could be done. Saturable autotransformer? Thanks bro

[@Gaelmalkavian]

Bloody Heeeeeeeell !!!!! love it !!!!

[@berys76]

This give an idea for a voltage multiplier without no semiconductors, spark gaps or vac tubes

[@_a.z]

Good description!

[@antraciet]

I have a simular regulator, i don't use it of course, but my father did for the tv in the seventies.

[@amkp40technology]

Amazing technology 👍🏻👍🏻❤️❤️🙏🏻🙏🏻

[@noco-pf3vj]

High output voltage than normal because one or all capacitors is out of spec. For 60 years old, it is still great though, much new ferroresonant voltage regulator output goes out of spec just 10 years of using.

[@pdrg]

An amazing bit of work, thanks for showing it well

[@chrismorley5393]

Really interesting video! :)

[@Pulverrostmannen]

Cool stuff back from the golden age

[@Basement-Science]

The capacitor on its own winding might also be due to the reduction in magnetic coupling when the core is saturated maybe. Even the physical placement of the different windings should make some difference here. Not sure how much though.

[@mahlapropyzm9180]

Fascinating. I was expecting it to be filled with Annunaki ectoplasm.

[@lmwlmw4468]

My parents used a very similar one for the Tv, and it regulated mains very well, as our mains back then used to go down to 160 Vac from the 220 Vac it should be.

[@mernok2001]

It should be now 230V not 220.

[@greatmateworkshop9764]

Back then was 220v, my dad still says 220v when he refers to mains voltage, he knows its 230v now, but it is difficult to change the habits.

[@LMB222]

Did your frequency also go down? I am trying to find out if the device can produce a stable 50Hz on the output.

[@DrBeat-zs9eb]

Coming back to the zener diode example: how can this increase the input voltage? I get how it decreases it

[@marc-andreservant201]

It can't. You need the input voltage to be strictly higher than the output voltage (and to step up DC you need active components). The AC version can increase the output voltage by adding a transformer stage (or as shown in the video, by using the inductor as a center tap transformer).

[@DrBeat-zs9eb]

@@marc-andreservant201 Okay, so the first AC example in the video (inductor in series and saturable inductor in parallel) can't increase the voltage too, right?

[@marc-andreservant201]

@@DrBeat-zs9eb No, it can only decrease the voltage (think of the impedances of the two inductors as a voltage divider). The equation is still Vout = Vin * Z2/(Z1+Z2), and the fact that Z2 is variable doesn't change the fact that the ratio is always less than 1.

[@vaclavtrpisovsky]

The 430 DM is _abzüglich_ or "after the discount". Hence the original price was around 575 DM or the equivalent of 1000~1200 €.

[@vaclavtrpisovsky]

@G E T R E K T 905 Well, I used the same value as Danyk did in his inflation calculation at 4:22.

[@LMB222]

And that's how much they cost today.

[@bluetrepidation]

If anyone is looking for one of these within USA check your local industrial controls shop for used industrial cabinets. Look for a beige transformer mounted to the outside with "SOLA" brand name. SOLA constant voltage transformer harmonic neutralized type CVS. These are used to protect the 120 v control power that supplies PLCs or larger motor drives. Can still be purchased new too. They work extremely well and last forever.

[@Tjousk]

Well explained, thanks.

[@leonardmilcin7798]

Look ma, no transistors!

[@DigitalBhangari]

The Germans could probably build an entire computer with just inductors

[@Basement-Science]

@ejsanyo01 I think he was only using relays, no purely magnetic logic circuits.

[@WolfgangMahringer]

Core memory...it basically consists of little inductors.

[@rilosvideos877]

@@WolfgangMahringer Yes, the whole RAM memory was mady with magnetic torus cores. They were fiddled in wires per hand and were extremly expensive in the 50ees. A core block of just 4 kB could cost a few 1000 $ monthly rate - they were not sold - just rented. Mostly to insurance companies - nobody could afford to buy them!

[@Omegaman1969]

My old Juke box has core memory, amazing that it is non volatile.