When I was developing aircraft instruments, we used two shake tables. One was inside a temperature/humidity environmental chamber, and the other was at the center of a 3m magnetic field cube. The one in the environmental chamber was dual axis (XY), and the other was single axis (Z). We had separate operational vibration profiles we had to put the instruments through to meet environmental specifications for propeller aircraft, jets and helicopters. Doing a full vibe test run would take nearly a week, assuming everything went well. We learned so much stuff on the shake tables. We used to pot our instruments, until a shake table test showed the potted instrument actually suffered damage easier than the unpotted one. So we went with only conformal coating instead. We also found that sheet metal changes from switching suppliers could greatly affect instrument resonances, despite the metal stock from each source meeting the same specifications. Which was fixed by pressing ribs into key areas, meaning we could use a wider variety of sheet stock. We used ultracaps for temporary backup power in some instruments. All of which failed vibe testing. We tested every ultracap Digikey carried. We had to get some made with custom mechanical changes (Maxwell was local to us), then support them in a metal cage that tailored the vibe spectrum the ultracaps encountered. That project alone occupied our shake tables for two months. Most shake tables can't deliver high amplitude impulses. When I was developing a super-rugged ultra-high-speed digital video camera we cared more about high level impulse response than vibrational modes. So we got to go a bit caveman: We mounted the camera to a large steel plate, attached a 3-axis reference accelerometer to it, then whacked the back of the plate with a sledgehammer, repeated with the camera mounted in 26 different orientations (6 faces, 12 edges, 8 corners). The camera was used inside cars during crash tests, and within 10 meters of missile warhead tests. It was rated for a lifetime of 100g impacts.
As a EE involved in designing avionics and electronics for earthmoving equipment, vibe testing was educational and often surprising. Earthmoving equipment was a worse vibration environment, as you'd expect when steel is hitting rock. We also had mixed results from potting. Hard potting was likely to break parts off the board when things heated up and cooled off. Soft potting was better for the board and parts, but didn't provide mechanical protection. Having a good mechanical engineer on the design team who had experience with encapsulants and potting was key to success!
A strobe light is a key accessory to vibe testing. I built a circuit to drive the strobe at a fixed offset frequency from the vibe drive frequency so the unit under test would display its motion at a fixed alias frequency like 5 Hz or so. I could tune it over about 1 - 10 Hz. It was great for frequency sweeps. It was confusing and fascinating at the same time. You would hear the drive frequency sweep while the motion rate was constant. Great fun and very convenient. You could spot critical resonance modes quickly and not miss any of them. I have exactly the same driver you showed and some larger ones like it. We use a 700W amp to drive them.
Great idea. Another idea could be using an Android smartphone with a good camera app than can set the shutter timing when recording video. Some phones even have a ultra-slow-motion recording function.
Hah, we built one of them for testing a battery drill, drilling a hole in perspex. The strobe was matched to the drill RPM so it looked like the drill bit was stationary as it made the hole.
Watching this channel for like 8 years now and hearing Dave complain about to220 "flapping around in the breeze" countless amount of times and now finally he has proven it, we're now fulfilled and can die in peace...
Oh, dear, I have 2 TO-220 linear voltage regulators, a beefy elco and a HC05 Bluetooth module flapping about in the breeze on my first board (one-off) that I have designed myself. Mind you I'm not an electronic engineer by any stretch of the imagination. Thanks to this video I now know what not do with that project and what to fix in the next version.
@@LarixusSnydes You mentioned.... " Mind you I'm not an electronic engineer by any stretch of the imagination." But thats still impressive, i couldnt do it. "He Sob's!"
I used to use a larger version of this to calibrate electromagnetic vibration sensors for testing Rolls Royce turbine engines. It was driven by a vacuum tube amplifier with 4 807's in push-pull parallel. Driven by a good old HP 200 signal generator. It used an electromagnet controlled by a Variac. A Bruel & Kjaer reel to reel was used to record the engine tests. A vintage Nicolet 446 spectrum analyzer did the analysis. The boards inside were all wire-wrapped TTL logic This setup ran for years with no problems except sometimes you had to whack the Nicolet to make it work. This was in the 1980's. There were no airplanes crashing or natural gas pumping stations blowing up so I guess it worked. At least the vibration tests were accurate.
The first company I worked for after leaving college made these, the size of houses, to test aerospace parts. They used 50Kw audio amps to drive them, like they used to use in football stadiums. Which consisted of hundreds of transistors bolted to water pipes in parallel. The most amazing thing about them was that everything and I mean everything would hit its resonant frequency when we did the test frequency sweeps. Even your vocal cords, if you kept your mouth wide open you would make sounds that you had no control over. Also the tube ceiling lights made from fine glass would flex by a couple of inches without breaking.
We used to use them to simulate human breathing into an oxygen cannula. Our products would sense the patient’s breathing via the pressure change in the nasal cannula and deliver a pulse of oxygen at the beginning of inhalation. We would use this in production to calibrate the trigger threshold. At least that’s what the modification could be used for. Great video. Brings back some old memories 😁
I remember using these with PCBs and strobe lighting to actually see how the loaded PCB distorts (perversely testing PCBs for Frequency Response Analysers) . The tall electrolytic caps would appear to sway about like skyscrapers in an earthquake. We wouldn't just use frequency sweeps though, we had recordings of road vibrations as felt in the boot (trunk) of a car or in the cargo hold of an airplane. Fun times!
You just demonstrated why the Air Force teaches the "High Reliability Soldering Techniques" course that I took 40 years ago. It stressed making solid physical connection and not using solder to bridge gaps because of vibration and thermal movement. I spent the last 30+ years as a civilian shaking my head at the bad soldering techniques in all the equipment I've repaired.
If AvE was reviewing this, they would be simple-entendres et fiers! Something like "The Good Lady seen a' adver-tisement sayin' some'n' 'boot some gi-normous electrodynamic vi-brator!"
A lot of people call them 'voice coils'. I was doing the vibration test on a product at a test house that had a 'car' sized shaker . one of their engineers hooked his bass guitar to it's 10,000W amp for 'testing'
Wow that was really interesting. I remember when we were calibrating the equalizer on the sound system at my church and we were sweeping the frequencies and found the resonant frequency of the room. It was the weirdest thing. I was walking around and could feel and hear the spots where I would be in standing waves, it was the weirdest thing. You would hit a spot that was super intense and loud, then hit a spot that was virtually silent. We turned it off because the wood panels on the walls were literally shaking and probably would have eventually shaken loose. We definitely turned that frequency way down on the equalizer lol.
Hey Dave.. Please repeat this with some new TO-220s, one flapping in the breeze, one down the the shoulders of the leads, one staggered pin arrangement, and one where "somebody had fun" as you often quote, gunked down to the PCB. It'd be good to get an appreciation of how much more securely the different mounting options work.. Not much point in trying a bolted to the PCB/heatsink version. I was soooo expecting a timelapse/ I'll leave it overnight video waiting for the failure, this happened much more quickly than I expected.
Another vibration sensitivity you will see with analog circuits is offsets induced due to flexing of the die inside the package. Once had to rotate a 14 pin dip thermocouple amp 90 degrees and add some mounting screws to reduce its sensitivity to the pcb flexing.
The ring that keeps the armature centered is called a 'Flexture'. On larger shakers, they use optical sensors and air bags that dynamically inflate/deflate depending on mass and keep the armature centered vertically in the stroke. They can also be configured for single-shot where you start at the bottom of stroke. We have also used 2 shakers and controlled the phase relationship. For serious vibration testing, a MAST (Multi-Axis Shaker Table) is used where you can control 6 degrees of freedom.
When I worked for Vipac Engineers and Scientists, we had a Ling 10KN shaker and Ling 16KW amplifier which, I worked on regularly. Wasn't as good as the B&K shaker though. I used to calibrate accelerometers using B&K charge amps, was an interesting job.
"mystery device from the bunker" sounds like my old days around 2004-2010, when I built vacuum tube electronics (some amps, a compressor-limiter etc.) for myself and a few buddies, and labeled them "Vault-Tec Electronics". Gives a good idea where I got my inspiration for electronics design, and getting interested in tubes in the first place :)
It looked like the resonance peak was moving when you turned up the amplitude the first time around 18:30, the tab deflection visibly decayed over a few seconds. I assume the material properties were already changing due to fatigue. Very cool demo,I always figured this was an effect that set in over like months of high vibration, not a worst case of several minutes.
Yeah, I would think the elasticity of the steel would decrease (but the mass stay the same) and so the frequency would drop. (from 110 to 95 apparently)
This bring back memories of when I worked for Racal. We had a 1KW Ling Altec vibration table. System came with a strobe light so you could easily see the big ceramic capacitors fly off the boards. One of the PCBs I recall used components that were all identical cubes. So the whole assembly was a solid block.
In my dayjob, I have to design for vibration and shock as well. I design spacecraft (satellite) electronics. Stuff needs to survive the shocks and vibration of launch. Our shakers are a lot larger than these, but the principle is the same. A lot of care is put on designing connector or wire interfaces with strain relief and proper mounting to PCBs. Shocks can rip SMT connectors clean off PCBs. Doing vibe analysis is an art form and some times it is counter intuitive. e.g. using glue / celastic to keep connectors from moving might affect the thermal expansion reliability, and lower the overall reliability. It's not simple at all!
@@WouterWeggelaar Or see just how it shows up on wet slug tantalum capacitors, especially as you get to the larger values, like 1000uF, which has a pretty heavy mass of sintered tantalum inside. Those were always both glued down with compliant compound, and also were tied down with lacing twine, with a drop of conformal coat holding the twine to the body, and then the whole lot was coated again. Had a few that actually broke free over time with vibration, and ended up rattling loose inside the housing.
@@SeanBZA yes, those tants were (are) very much an "only use when you can't avoid" type of component. Not to mention reliability issues with them in general... I usually manage to avoid them now that ceramics have improved so much! Luckily, do radio, not power 😂
The test is called experimental modal analysis. The goal is to measure the frequency mechanical response (acceleration) of structures under controlled sinusoidal excitation (displacement). It is strongly connected to the eigenfunctions of the mechanical wave equation. The goal is to find any ressonances and compensate using dynamic dampers.
My high-school work experience placement was on premises for shake and insulation testing of power station transformers for high risk installations in earthquake zones. That was a fun week!
Suddenly I am reminded of cheap RTC modules where the clock crystal is a metal cylinder held to the board by 2 thin radial leads. There's usually a solder pad to attach the case of the crystal to it, but it's almost never actually soldered to it. Seems that it would snap off quite easily when subjected to such vibrations
ive actually seen that happen on some refrigeration control modules.My girlfriend brought a bunch home which had been returned as "faulty", and thats exactly what had happened to them!
We have a small shaker system, from memory is was a cube of steel about 1ft square and it had a couple of shaker motors fixed to it, so you could apply the vibrations in two planes. We used it mainly to look for issues in the cases and metalwork for the equipment. The steel block had various mounting holes and slots so that you could bolt the item down to it. With an added strobe you could easily see the metalwork moving, in some cases an inch or more. so you soon found out where additional fixing was required, either to the electronics or the actual metalwork. Wired up the the side of the control cabinet was the remains of one of the output tubes. I have no idea now as to the output power, but this tube was about 18 inches long and 5 or 6 inches in diameter, it must have been a couple of thousand watts or so. The tube had a long crack in the side, There was a pair of these in push-pull for each motor. Andy
This was manufactured in my small home town of Royston, Hertfordshire! Incredible! I knew we had quite a vibrant industry here back in the day, but it’s mostly died off now, aside from Johnson Matthey.
I worked in electronics repair for a few years and yes I have seen TO220 and other parts break solder joints. That is usually the first place you want to look.
That was an amazing video. Regarding the adapter: I could also see it being used to create a directed, defined sine wave to test response frequencies of pressure systems. The tubing can cause non-linear effects on the amplitude and phase during transient pressure gradients compared to the actual measure point. With the shaker you would be able to experimentally determine the transfer functions to correct the errors
My very first guess on seeing that acrylic interface with a rubber gasket or diaphragm under it, was that this thing was being used as a 'tube speaker' for pumping audio waves through a tube. There's a few applications for this, it's done in "talkbox" funk music effects, and it also used to be how many airline headphone systems worked.
Yep - I work in the industry for one of the major players, but I work on DSAs and Vibration Controllers. We have our own shaker lines too; and I actually have that very shaker sitting on my desk that I use to test our vibration control software! For anyone who is wondering, a tiny shaker like that will run you USD ~4-8k, plus another 1-2k for the amplifier. Nowadays these small size shakers are mostly used by Universities for teaching, or medical device companies who have strict standards they need to abide by. As Dave mentioned small PCBs' dont get tested much as their dynamic properties make them less susceptible to vibration damage by common vibration environments (transportation, etc); but larger PCBs do go through more rigorous testing.
Dave! Please do a vid about calibration in general. Is calibration always needed or is it more for the paperwork? I know if a product fails then it is always better to have as much documentation as possible. For hobby work I dont know how much it matters.
Yes! And also include some of the instrument design decisions needed to 1) ensure it CAN be calibrated, and 2) ensure it will STAY calibrated. Those fancy digital calibrations all the cool kids have these days take all the fun out of it. And GET OFF MY LAWN!
i used to do a lot of environmental testing of military electronics at Avco labs. They had shakers that could handle rockets and medium tanks. A lot of the smaller shakers were vacuum tube based, they were all water cooled. We made power supplies and they had to undergo all kinds of qualification tests, we used strobe lights so we could watch things twist and bend when you hit a resonance mode. Ive seen 3/16" thick angle braces that secured heavy transformers to a chassis crack and fail during a sweep and dwell test. One day i wandered over to the next bay and they were testing a USAF hydrogen bomb - luckily the trigger had been removed.
I have seen a very interesting application of this: In WW2, I think, magnetic bombs were made to explode when the metal bottom of a ship's hull approached it. This was defeated by DE-GAUSSING the ship's hull by 'degaussing engineers'. Then the opposition created 'sound bombs' set off by the ship's engines. The countermeasure for this was a pyramid-shaped "speaker-like" device that used a large underwater oscillator very similar to that oscillator. These under-water "speakers" generated far-range water oscillations which could trigger the explosive before the ship was too close to be damaged. PS I am always amazed at the clever engineering inspired in war! ... remember the air balloon bombs with the 'dropping weights sent to America via the Gulf stream.
When I saw the whole device I immediately thought it is a driphragm pump, and looks like it was modded into one. Diaprhragm pumps are nice, because they enable you to reach high pressure with low flow. The one I have is able to reach 5 bar at 50 ml-2l flow. It used to be a part of industrial waste recycling plant, pumping reagent into the reservoir. It is really just a solenoid coupled with a diaphragm and a valve. Mine has frequency and flow / throw regulation already in, so it only needed mains to function (but it has an external control port). Sadly I have no use of it, but it is an intersting piece.
When I was an electronics tech we had a shaker as big as the biggest one you showed, we shook the heck out of parts while examining them with a strobe light to see how well things were dealing with the G forces.
That's adorable! I work in the aerospace industry and our older vibe tables are are the size of small lorries. The new ones integrate vibration and temperature in a single chamber.
That one is so cute. Never knew they made them that small. I am currently operating a significantly larger, multi-axis table, where we shake aircraft communication gear. 6G RMS of random vibration, from 20 to 1000Hz.
Looks like it was coupled to a silicone fluid media, to provide pressure pulses of calibratable amplitude, likely to drive some sort of cylinder for motion, or more likely to provide a pressure wave in some sensor. Got some of the companion vibration sensors, that are normally used to provide vibration sensing. Did use one attached to a old full height SCSI drive to record the bearing and motor noise during start up ,including the head coil motion.
You can also try doubling or halving the frequency to see if that frequency is even more violent, if you are trying to find the real resonant frequency. Octaves will still resonate, just not as violently.
We used to use less robust versions of these in a school physics department to show resonant frequencies. If anyone is looking for one to play with, a look at educational suppliers may provide a cheap alternative.
A company we used to collaborate with at my previous employer built their own little shaker by modifying a high power subwoofer with a mounting plate instead of the paper cone. That device pre-tested several generations of industrial analytical instruments against vibration.
In that company, we bought our own shaker from Alibaba, because the equipment we made usually came packed in a big stainless steel chassis (Ex d equipment), so an instrument was something like 3-4 kg easily. It was about the same price as one or two days at the test lab, but the issue was it was setting up this massive electromagnetic field from the shaker solenoid! It induced so much noise into the instrument, that we couldn't use it. We had to add a massive ferrous cast iron box around the DUT to shield it. It eventually worked, but was much less practical than expected :P
at my last job we bought a small shaker table second hand to measure vibration response of a motion-compensated airborne camera. after a while something in either the shaker or its power amp died (we actually sent the amp back to the manufacturer to replace some components but it didn't fix the real issue). so we found a local university with a packaging science shock and vibe lab, which was nice because their bigger pneumatic table could handle much larger assemblies. they also had one built into the floor that was the size of a car, and a few other instruments like drop testers.
Back in the 90's I bought a complete B&K vibration test system for $600 at a Telstra auction and have used it as part of design verification for some of my customers. Since then I've bought extra B&K accelerometers and charge amps but the B&K sensor I like the best is a hammer with an accelerometer. So I can genuinely say I have a calibrated hammer!
Accurate portrayal of Radio Telephones for Courier Motorcycles (mid 1980's when I worked on them). 6 months was the maximum lifespan. Whereas cars wouldn't bother them at all.
Years ago I did my 2 weeks of school work experience at Woolwich Arsenal 'Central Packaging Unit'. Sounds boring but they made packages for the military. e.g. a crate for a tank axle that could be thrown out of an aeroplane, maybe in a desert or the arctic. Loads of equipment for shaking, dropping, freezing or baking. Rattled your teeth for sure.
i haven't thought about shake and bake testing for a while. my old lab had thermotron cabinets for environmental testing, but i don't remember what we used for the huge vibe tests. we had some pretty energetic test to failures lol. i'll never forget a customer asking if we had to damage their test unit during the test to failure...
I repaired digital clock and radio in my friends car. Both had cracks in solder joints on SMD components. Radio had obviously unsupported part of PCB where cracks occurred.
Currently working for a company that does this stuff. We produce shakers and the measurement systems mostly for sensor calibration at the production facility. We also do structural modal analysis. The surprising thing for me was that precision in this field is very expensive, for example a calibration system for sensors with a accuracy of 1% is in the 5 digit $ range. Building a good shaker is really where the money goes into.
Could this vibration be the reason why a lot of ultrasonic cleaners fail, perhaps the frequencies are coupling into the PCBs in them never give it a thought before, Great example 👍
This reminds me my apprentice year in the electronic factory, where at one point in time I was given the duty of keeping an eye on the big microwave shaker/cleaner, in which the finished boards were examined. In many cases I was fishing for broken off components the ones which had not been soldered properly.
I used to work for an avionics manufacturer, and we had a specific audio unit that we made that the Indian Army went a bit overboard with. The army mounted the unit next to the machine guns in their helicopters and all of the SMD capacitors flew off! From them on, we had to use some pretty good glue to hold them down...
"Why are avionics (aircraft radios and such) so expensive compared to other similar electronics?", I always asked... until now. At 21:04, where the TO-220 is flapping and breaks off, the sound frequency is remarkably similar to the sound and likely the same vibration frequency of a piston propeller aircraft inflight.
Be a different frequency, but imagine what it would be like if it had a small free-floating heat-sink with fins mounted to the regulator. Even if it didn't break right away, would the heat sink wave around enough to touch some other component and short. I'm sure in high-vibration applications they have to consider an 'envelope' for vibrating motion around parts.
We used to have a horizontal and vertical shaker made by ling in the environmental test department (AKA the Shake and Bake department). Ours could handle several tonnes it was mostly used for large marine HF radios.
I used to calibrate crash data recorder bricks using something similar, but much larger. I remember seeing it pulling 4KW during the more severe shaking. The platform was maybe about half a meter in diameter and had to be backed up with compressed air because it weighed a ton. Literally. Other than the data recorders, avionics boards for spacecraft and satellites were also shake tested. The whole thing was driven with an old IBM PS/2 machine with the glorious and legendary Model M clicky keyboard.
We have a very simple yet expensive engine start tool for truck APUs, for maintenance, it's 500$ and they don't secure the voltage regulator, after a short amount of time it snapped off, had to get a new tool, I open the new one, same thing, I had to use 5$ silicone to secure it.
These are cool. Combined with high speed imaging and Euler filtering, small oscillations can be amplified to see minute motion in an assembly, helping to identify potential modes of failure without destructive testing!
Fascinating! I have two of these in my shop - bought off eBay for $5-10 each a few years back. They were made by Griffin George for use in schools in the UK, for wave table and plates-with-salt experiments. Time to dig them out I think....
In refection to unusual devices we see today called "acoustic transducers" which are basically a speaker driver minus the speaker cone . in this case they attach a heavy physical mass to the electromagnetic driver coil feed it the bass signal from LBE channel of a multi track audio film , then the device is mounted to chair you sit in so that the viewer can feel the LBE effects in the film and you don't drive the neighbors insane by playing a sub woofer at high levels .. A number of 4D cinemas like Disney's Avatar, flight of passage use this technology to make the experience more immersive , I do realize the device your showing , apply s the frequency directly to the object being tested instead for example testing a circut board being used in rockets navigation system that would exposed to all kinds of extreme vibrations for issues with component harmonics.
we had 2500 pounders where I worked in the late 1950's. Aviation secondary power systems for military jet aircraft. They had huge permanent magnets. They'd take a 12 inch Crescent wrench out of your hands if you got too close. Water cooled. We used, mostly, dental cement to attach sensors. Epoxy had just been invented, I think. BTW, about half of our test equipment was still vacuum tubes.
When I was developing aircraft instruments, we used two shake tables. One was inside a temperature/humidity environmental chamber, and the other was at the center of a 3m magnetic field cube. The one in the environmental chamber was dual axis (XY), and the other was single axis (Z). We had separate operational vibration profiles we had to put the instruments through to meet environmental specifications for propeller aircraft, jets and helicopters. Doing a full vibe test run would take nearly a week, assuming everything went well.
We learned so much stuff on the shake tables. We used to pot our instruments, until a shake table test showed the potted instrument actually suffered damage easier than the unpotted one. So we went with only conformal coating instead. We also found that sheet metal changes from switching suppliers could greatly affect instrument resonances, despite the metal stock from each source meeting the same specifications. Which was fixed by pressing ribs into key areas, meaning we could use a wider variety of sheet stock. We used ultracaps for temporary backup power in some instruments. All of which failed vibe testing. We tested every ultracap Digikey carried. We had to get some made with custom mechanical changes (Maxwell was local to us), then support them in a metal cage that tailored the vibe spectrum the ultracaps encountered. That project alone occupied our shake tables for two months.
Most shake tables can't deliver high amplitude impulses. When I was developing a super-rugged ultra-high-speed digital video camera we cared more about high level impulse response than vibrational modes. So we got to go a bit caveman: We mounted the camera to a large steel plate, attached a 3-axis reference accelerometer to it, then whacked the back of the plate with a sledgehammer, repeated with the camera mounted in 26 different orientations (6 faces, 12 edges, 8 corners). The camera was used inside cars during crash tests, and within 10 meters of missile warhead tests. It was rated for a lifetime of 100g impacts.
Thanks for the awesome story Bob!
That is cool as shit! Thanks for sharing!
As a EE involved in designing avionics and electronics for earthmoving equipment, vibe testing was educational and often surprising. Earthmoving equipment was a worse vibration environment, as you'd expect when steel is hitting rock. We also had mixed results from potting. Hard potting was likely to break parts off the board when things heated up and cooled off. Soft potting was better for the board and parts, but didn't provide mechanical protection. Having a good mechanical engineer on the design team who had experience with encapsulants and potting was key to success!
That's incredibly interesting!
Cheers to our aviators and engineers.
A strobe light is a key accessory to vibe testing. I built a circuit to drive the strobe at a fixed offset frequency from the vibe drive frequency so the unit under test would display its motion at a fixed alias frequency like 5 Hz or so. I could tune it over about 1 - 10 Hz. It was great for frequency sweeps. It was confusing and fascinating at the same time. You would hear the drive frequency sweep while the motion rate was constant. Great fun and very convenient. You could spot critical resonance modes quickly and not miss any of them. I have exactly the same driver you showed and some larger ones like it. We use a 700W amp to drive them.
Great idea. Another idea could be using an Android smartphone with a good camera app than can set the shutter timing when recording video. Some phones even have a ultra-slow-motion recording function.
I've always relied on the Mk1 eyeball. We never used to film vibration testing, all we ever wanted was the numerical and physical results.
A rolling shutter off-axis and at less than 1/2f also reveals quite a bit.
Put in a frame, make a nice box and you have a product which you can sell for hundreds of quids! th-cam.com/video/0c20FCZr9Hs/w-d-xo.html
Hah, we built one of them for testing a battery drill, drilling a hole in perspex. The strobe was matched to the drill RPM so it looked like the drill bit was stationary as it made the hole.
Watching this channel for like 8 years now and hearing Dave complain about to220 "flapping around in the breeze" countless amount of times and now finally he has proven it, we're now fulfilled and can die in peace...
Yes we can. As i write these last words, i expell my last breath in this eccentric world of Dave.
Oh, dear, I have 2 TO-220 linear voltage regulators, a beefy elco and a HC05 Bluetooth module flapping about in the breeze on my first board (one-off) that I have designed myself. Mind you I'm not an electronic engineer by any stretch of the imagination. Thanks to this video I now know what not do with that project and what to fix in the next version.
@@LarixusSnydes You mentioned.... " Mind you I'm not an electronic engineer by any stretch of the imagination." But thats still impressive, i couldnt do it. "He Sob's!"
@@groovejet33 see yah!
@@LarixusSnydes you could also attach a TO-220 heatsink to the VR.
Oh, I gotta get me one of those!
Definitely! Better quality control for Frantone pedals for sure :)
With 3D printed accessories on top this could be interesting for sure.
You'll have a lot more luck getting a used one in the US than I would.
Filthy!
FranTone Comes Alive!
I used to use a larger version of this to calibrate electromagnetic vibration sensors for testing Rolls Royce turbine engines.
It was driven by a vacuum tube amplifier with 4 807's in push-pull parallel.
Driven by a good old HP 200 signal generator.
It used an electromagnet controlled by a Variac.
A Bruel & Kjaer reel to reel was used to record the engine tests.
A vintage Nicolet 446 spectrum analyzer did the analysis. The boards inside were all
wire-wrapped TTL logic
This setup ran for years with no problems except sometimes you had to whack the Nicolet to make it work.
This was in the 1980's.
There were no airplanes crashing or natural gas pumping stations blowing up so I guess it worked. At least the vibration tests were accurate.
The first company I worked for after leaving college made these, the size of houses, to test aerospace parts. They used 50Kw audio amps to drive them, like they used to use in football stadiums. Which consisted of hundreds of transistors bolted to water pipes in parallel. The most amazing thing about them was that everything and I mean everything would hit its resonant frequency when we did the test frequency sweeps. Even your vocal cords, if you kept your mouth wide open you would make sounds that you had no control over. Also the tube ceiling lights made from fine glass would flex by a couple of inches without breaking.
That is wild! I would love to see a 50 kw amp
We used to use them to simulate human breathing into an oxygen cannula. Our products would sense the patient’s breathing via the pressure change in the nasal cannula and deliver a pulse of oxygen at the beginning of inhalation.
We would use this in production to calibrate the trigger threshold. At least that’s what the modification could be used for.
Great video. Brings back some old memories 😁
This exact one was probably used for something like that.
I remember using these with PCBs and strobe lighting to actually see how the loaded PCB distorts (perversely testing PCBs for Frequency Response Analysers) . The tall electrolytic caps would appear to sway about like skyscrapers in an earthquake. We wouldn't just use frequency sweeps though, we had recordings of road vibrations as felt in the boot (trunk) of a car or in the cargo hold of an airplane. Fun times!
You just demonstrated why the Air Force teaches the "High Reliability Soldering Techniques" course that I took 40 years ago. It stressed making solid physical connection and not using solder to bridge gaps because of vibration and thermal movement. I spent the last 30+ years as a civilian shaking my head at the bad soldering techniques in all the equipment I've repaired.
If AvE was reviewing this it would be a double-entendre fiesta
A treat especial!
@@WouterWeggelaar For the missus.
This would definitely be one of the pieces to go into the Cockford-Ollie.
If AvE was reviewing this, they would be simple-entendres et fiers! Something like "The Good Lady seen a' adver-tisement sayin' some'n' 'boot some gi-normous electrodynamic vi-brator!"
A lot of people call them 'voice coils'. I was doing the vibration test on a product at a test house that had a 'car' sized shaker . one of their engineers hooked his bass guitar to it's 10,000W amp for 'testing'
Maybe that's what the giant guitar amp at the beginning of _Back To the Future_ was supposed to be.
Yeah i'm 100% sure he played the white stripes, no way he didn't.
Wow that was really interesting. I remember when we were calibrating the equalizer on the sound system at my church and we were sweeping the frequencies and found the resonant frequency of the room. It was the weirdest thing. I was walking around and could feel and hear the spots where I would be in standing waves, it was the weirdest thing. You would hit a spot that was super intense and loud, then hit a spot that was virtually silent. We turned it off because the wood panels on the walls were literally shaking and probably would have eventually shaken loose. We definitely turned that frequency way down on the equalizer lol.
Hey Dave.. Please repeat this with some new TO-220s, one flapping in the breeze, one down the the shoulders of the leads, one staggered pin arrangement, and one where "somebody had fun" as you often quote, gunked down to the PCB. It'd be good to get an appreciation of how much more securely the different mounting options work.. Not much point in trying a bolted to the PCB/heatsink version.
I was soooo expecting a timelapse/ I'll leave it overnight video waiting for the failure, this happened much more quickly than I expected.
Also please do a 220 with a heat sink.
@@bertblankenstein3738 A small heatsink attached to the TO220 but still flapping in the breeze!
_Not much point in trying a bolted to the PCB/heatsink version._
Sure there is. Every good experiment needs a control.
Another vibration sensitivity you will see with analog circuits is offsets induced due to flexing of the die inside the package. Once had to rotate a 14 pin dip thermocouple amp 90 degrees and add some mounting screws to reduce its sensitivity to the pcb flexing.
The ring that keeps the armature centered is called a 'Flexture'. On larger shakers, they use optical sensors and air bags that dynamically inflate/deflate depending on mass and keep the armature centered vertically in the stroke. They can also be configured for single-shot where you start at the bottom of stroke. We have also used 2 shakers and controlled the phase relationship. For serious vibration testing, a MAST (Multi-Axis Shaker Table) is used where you can control 6 degrees of freedom.
When I worked for Vipac Engineers and Scientists, we had a Ling 10KN shaker and Ling 16KW amplifier which, I worked on regularly. Wasn't as good as the B&K shaker though. I used to calibrate accelerometers using B&K charge amps, was an interesting job.
"mystery device from the bunker" sounds like my old days around 2004-2010, when I built vacuum tube electronics (some amps, a compressor-limiter etc.) for myself and a few buddies, and labeled them "Vault-Tec Electronics". Gives a good idea where I got my inspiration for electronics design, and getting interested in tubes in the first place :)
Great stuff! I've missed your longer videos where you really dive into something and do practical tests.
I really liked this video. Didn’t know such thing existed. Very fun and entertaining.
It looked like the resonance peak was moving when you turned up the amplitude the first time around 18:30, the tab deflection visibly decayed over a few seconds. I assume the material properties were already changing due to fatigue. Very cool demo,I always figured this was an effect that set in over like months of high vibration, not a worst case of several minutes.
Yeah, I would think the elasticity of the steel would decrease (but the mass stay the same) and so the frequency would drop. (from 110 to 95 apparently)
This bring back memories of when I worked for Racal. We had a 1KW Ling Altec vibration table. System came with a strobe light so you could easily see the big ceramic capacitors fly off the boards. One of the PCBs I recall used components that were all identical cubes. So the whole assembly was a solid block.
17:55 That sounds exactly like Marty McFly pumping up the volume on the massive speaker at Doc's home.
Been watching for years, just wanted to say thanks for the awesome videos.
In my dayjob, I have to design for vibration and shock as well. I design spacecraft (satellite) electronics. Stuff needs to survive the shocks and vibration of launch. Our shakers are a lot larger than these, but the principle is the same.
A lot of care is put on designing connector or wire interfaces with strain relief and proper mounting to PCBs. Shocks can rip SMT connectors clean off PCBs.
Doing vibe analysis is an art form and some times it is counter intuitive. e.g. using glue / celastic to keep connectors from moving might affect the thermal expansion reliability, and lower the overall reliability. It's not simple at all!
Oh, one thing to show perhaps is the piezoelectric effect of parts like ceramic capacitors!
@@WouterWeggelaar Or see just how it shows up on wet slug tantalum capacitors, especially as you get to the larger values, like 1000uF, which has a pretty heavy mass of sintered tantalum inside. Those were always both glued down with compliant compound, and also were tied down with lacing twine, with a drop of conformal coat holding the twine to the body, and then the whole lot was coated again. Had a few that actually broke free over time with vibration, and ended up rattling loose inside the housing.
@@SeanBZA yes, those tants were (are) very much an "only use when you can't avoid" type of component.
Not to mention reliability issues with them in general...
I usually manage to avoid them now that ceramics have improved so much!
Luckily, do radio, not power 😂
The test is called experimental modal analysis. The goal is to measure the frequency mechanical response (acceleration) of structures under controlled sinusoidal excitation (displacement). It is strongly connected to the eigenfunctions of the mechanical wave equation. The goal is to find any ressonances and compensate using dynamic dampers.
Thank you so much. Those are certainly things to look out for.
I think Bill Haley and the Comets had one of these firmly in mind when they wrote the song "Shake, Rattle and Roll"!
My high-school work experience placement was on premises for shake and insulation testing of power station transformers for high risk installations in earthquake zones. That was a fun week!
That was great! 😂👍 You've got it in video!
I'm too, before that, seen only results of shaking as broken legs near packaging, lose solder joints etc..
Suddenly I am reminded of cheap RTC modules where the clock crystal is a metal cylinder held to the board by 2 thin radial leads. There's usually a solder pad to attach the case of the crystal to it, but it's almost never actually soldered to it. Seems that it would snap off quite easily when subjected to such vibrations
ive actually seen that happen on some refrigeration control modules.My girlfriend brought a bunch home which had been returned as "faulty", and thats exactly what had happened to them!
We have a small shaker system, from memory is was a cube of steel about 1ft square and it had a couple of shaker motors fixed to it, so you could apply the vibrations in two planes.
We used it mainly to look for issues in the cases and metalwork for the equipment. The steel block had various mounting holes and slots so that you could bolt the item down to it.
With an added strobe you could easily see the metalwork moving, in some cases an inch or more. so you soon found out where additional fixing was required, either to the electronics or the actual metalwork.
Wired up the the side of the control cabinet was the remains of one of the output tubes. I have no idea now as to the output power, but this tube was about 18 inches long and 5 or 6 inches in diameter, it must have been a couple of thousand watts or so. The tube had a long crack in the side, There was a pair of these in push-pull for each motor.
Andy
Obviously it's a turboencabulator.
Surmounted on a bed of prefamulated amulite.
This was manufactured in my small home town of Royston, Hertfordshire! Incredible! I knew we had quite a vibrant industry here back in the day, but it’s mostly died off now, aside from Johnson Matthey.
The main industry in Royston now seems to be buidling massive housing estates 😞
Fascinating on many points! Thanks for that.
Always fascinating to discover another vital but uncommonly known industry. Thanks for sharing Dave!
I worked in electronics repair for a few years and yes I have seen TO220 and other parts break solder joints. That is usually the first place you want to look.
That was an amazing video. Regarding the adapter: I could also see it being used to create a directed, defined sine wave to test response frequencies of pressure systems. The tubing can cause non-linear effects on the amplitude and phase during transient pressure gradients compared to the actual measure point. With the shaker you would be able to experimentally determine the transfer functions to correct the errors
My very first guess on seeing that acrylic interface with a rubber gasket or diaphragm under it, was that this thing was being used as a 'tube speaker' for pumping audio waves through a tube. There's a few applications for this, it's done in "talkbox" funk music effects, and it also used to be how many airline headphone systems worked.
Thanks - I learned something totally new today!
Yep - I work in the industry for one of the major players, but I work on DSAs and Vibration Controllers. We have our own shaker lines too; and I actually have that very shaker sitting on my desk that I use to test our vibration control software!
For anyone who is wondering, a tiny shaker like that will run you USD ~4-8k, plus another 1-2k for the amplifier. Nowadays these small size shakers are mostly used by Universities for teaching, or medical device companies who have strict standards they need to abide by. As Dave mentioned small PCBs' dont get tested much as their dynamic properties make them less susceptible to vibration damage by common vibration environments (transportation, etc); but larger PCBs do go through more rigorous testing.
Dave! Please do a vid about calibration in general. Is calibration always needed or is it more for the paperwork? I know if a product fails then it is always better to have as much documentation as possible. For hobby work I dont know how much it matters.
Yes! And also include some of the instrument design decisions needed to 1) ensure it CAN be calibrated, and 2) ensure it will STAY calibrated.
Those fancy digital calibrations all the cool kids have these days take all the fun out of it. And GET OFF MY LAWN!
Great Video. Thanks for going thru the explanation.
we used to do standing wave experiments with these equipment..totally loved it..
I have made many repairs of car amps that were mounted to the subwoofer. Many broken parts from vibration.
18:22 reminds me to the times, when i tuned vibratory feeders. Nice video!
i used to do a lot of environmental testing of military electronics at Avco labs. They had shakers that could handle rockets and medium tanks. A lot of the smaller shakers were vacuum tube based, they were all water cooled. We made power supplies and they had to undergo all kinds of qualification tests, we used strobe lights so we could watch things twist and bend when you hit a resonance mode. Ive seen 3/16" thick angle braces that secured heavy transformers to a chassis crack and fail during a sweep and dwell test.
One day i wandered over to the next bay and they were testing a USAF hydrogen bomb - luckily the trigger had been removed.
I have seen a very interesting application of this: In WW2, I think, magnetic bombs were made to explode when the metal bottom of a ship's hull approached it. This was defeated by DE-GAUSSING the ship's hull by 'degaussing engineers'.
Then the opposition created 'sound bombs' set off by the ship's engines. The countermeasure for this was a pyramid-shaped "speaker-like" device that used a large underwater oscillator very similar to that oscillator. These under-water "speakers" generated far-range water oscillations which could trigger the explosive before the ship was too close to be damaged.
PS
I am always amazed at the clever engineering inspired in war! ... remember the air balloon bombs with the 'dropping weights sent to America via the Gulf stream.
This explains the silicone/glue on those big capacitors and inductors.
“That’s what she said?” - You tell her be careful she's liable to chip a tooth!
When I saw the whole device I immediately thought it is a driphragm pump, and looks like it was modded into one.
Diaprhragm pumps are nice, because they enable you to reach high pressure with low flow. The one I have is able to reach 5 bar at 50 ml-2l flow. It used to be a part of industrial waste recycling plant, pumping reagent into the reservoir. It is really just a solenoid coupled with a diaphragm and a valve. Mine has frequency and flow / throw regulation already in, so it only needed mains to function (but it has an external control port). Sadly I have no use of it, but it is an intersting piece.
When I was an electronics tech we had a shaker as big as the biggest one you showed, we shook the heck out of parts while examining them with a strobe light to see how well things were dealing with the G forces.
If i could give you a bigger thumbs up I would. Would love a PCB dynamic testing series.
That's adorable! I work in the aerospace industry and our older vibe tables are are the size of small lorries. The new ones integrate vibration and temperature in a single chamber.
I wonder what happened to the circuitry inside the package. An O-scope before and after would be cool. Thanks for posting Dave.
That one is so cute. Never knew they made them that small. I am currently operating a significantly larger, multi-axis table, where we shake aircraft communication gear. 6G RMS of random vibration, from 20 to 1000Hz.
Looks like it was coupled to a silicone fluid media, to provide pressure pulses of calibratable amplitude, likely to drive some sort of cylinder for motion, or more likely to provide a pressure wave in some sensor. Got some of the companion vibration sensors, that are normally used to provide vibration sensing. Did use one attached to a old full height SCSI drive to record the bearing and motor noise during start up ,including the head coil motion.
You can also try doubling or halving the frequency to see if that frequency is even more violent, if you are trying to find the real resonant frequency. Octaves will still resonate, just not as violently.
Wouldn't this be more affected by odd-numbered harmonics than even-numbered? It's the odds that add up into square waves.
never seen such a thing. Great experiment
We used to use less robust versions of these in a school physics department to show resonant frequencies. If anyone is looking for one to play with, a look at educational suppliers may provide a cheap alternative.
I have been liking the new graphics you have been putting on the vids
A company we used to collaborate with at my previous employer built their own little shaker by modifying a high power subwoofer with a mounting plate instead of the paper cone. That device pre-tested several generations of industrial analytical instruments against vibration.
In that company, we bought our own shaker from Alibaba, because the equipment we made usually came packed in a big stainless steel chassis (Ex d equipment), so an instrument was something like 3-4 kg easily. It was about the same price as one or two days at the test lab, but the issue was it was setting up this massive electromagnetic field from the shaker solenoid! It induced so much noise into the instrument, that we couldn't use it. We had to add a massive ferrous cast iron box around the DUT to shield it. It eventually worked, but was much less practical than expected :P
Mounted on the top was a ddiaphragm pump with what looks like a leur lock connection at the top, possibly it was some sort of medical pump.
at my last job we bought a small shaker table second hand to measure vibration response of a motion-compensated airborne camera. after a while something in either the shaker or its power amp died (we actually sent the amp back to the manufacturer to replace some components but it didn't fix the real issue). so we found a local university with a packaging science shock and vibe lab, which was nice because their bigger pneumatic table could handle much larger assemblies. they also had one built into the floor that was the size of a car, and a few other instruments like drop testers.
Back in the 90's I bought a complete B&K vibration test system for $600 at a Telstra auction and have used it as part of design verification for some of my customers. Since then I've bought extra B&K accelerometers and charge amps but the B&K sensor
I like the best is a hammer with an accelerometer. So I can genuinely say I have a calibrated hammer!
Accurate portrayal of Radio Telephones for Courier Motorcycles (mid 1980's when I worked on them). 6 months was the maximum lifespan. Whereas cars wouldn't bother them at all.
NICE FIND!!! You found yourself a Flux-Capacitor!
Years ago I did my 2 weeks of school work experience at Woolwich Arsenal 'Central Packaging Unit'. Sounds boring but they made packages for the military. e.g. a crate for a tank axle that could be thrown out of an aeroplane, maybe in a desert or the arctic.
Loads of equipment for shaking, dropping, freezing or baking. Rattled your teeth for sure.
In the audio world, it's called a driver as it has no cone, hence not a speaker.
Gives a new meaning to Vibrators!
😁
i haven't thought about shake and bake testing for a while. my old lab had thermotron cabinets for environmental testing, but i don't remember what we used for the huge vibe tests. we had some pretty energetic test to failures lol. i'll never forget a customer asking if we had to damage their test unit during the test to failure...
I repaired digital clock and radio in my friends car. Both had cracks in solder joints on SMD components. Radio had obviously unsupported part of PCB where cracks occurred.
I've used small multi vector shaker tables large enough to test smps.
You can get the caps and transformers to hit the wall if you give it the beans.
Very cool Dave, love it
There was an instrument company called Wayne-Kerr, it always got a laugh from the girls on production when a call went out on the Tannoy.
So Sandy Munro asks why there is so many fasteners on automotive PCBs... that's why.
Currently working for a company that does this stuff. We produce shakers and the measurement systems mostly for sensor calibration at the production facility. We also do structural modal analysis. The surprising thing for me was that precision in this field is very expensive, for example a calibration system for sensors with a accuracy of 1% is in the 5 digit $ range. Building a good shaker is really where the money goes into.
We use shaker tables to test VFDs, some weighing more than a ton.
Maanwhile, 3 floors below the residents are looking up at the ceiling wondering what Dave is up to now.
Could this vibration be the reason why a lot of ultrasonic cleaners fail, perhaps the frequencies are coupling into the PCBs in them never give it a thought before, Great example 👍
Like my friend Dan says... THAT WAS DAN! ENJOYABLE. Very COoL. I'm ALL shook up!
Awesome - the perfect christmas present for my wife :)
It will replace you... being better.
Acoustic transducer. They also built vibration testing equipment.
This reminds me my apprentice year in the electronic factory, where at one point in time I was given the duty of keeping an eye on the big microwave shaker/cleaner, in which the finished boards were examined. In many cases I was fishing for broken off components the ones which had not been soldered properly.
I used to work for an avionics manufacturer, and we had a specific audio unit that we made that the Indian Army went a bit overboard with. The army mounted the unit next to the machine guns in their helicopters and all of the SMD capacitors flew off!
From them on, we had to use some pretty good glue to hold them down...
21:20 the Houdini moment. Who needs a -12v Voltage regulator anyway?
"Why are avionics (aircraft radios and such) so expensive compared to other similar electronics?", I always asked... until now. At 21:04, where the TO-220 is flapping and breaks off, the sound frequency is remarkably similar to the sound and likely the same vibration frequency of a piston propeller aircraft inflight.
Be a different frequency, but imagine what it would be like if it had a small free-floating heat-sink with fins mounted to the regulator. Even if it didn't break right away, would the heat sink wave around enough to touch some other component and short. I'm sure in high-vibration applications they have to consider an 'envelope' for vibrating motion around parts.
We used to have a horizontal and vertical shaker made by ling in the environmental test department (AKA the Shake and Bake department). Ours could handle several tonnes it was mostly used for large marine HF radios.
I used to calibrate crash data recorder bricks using something similar, but much larger. I remember seeing it pulling 4KW during the more severe shaking. The platform was maybe about half a meter in diameter and had to be backed up with compressed air because it weighed a ton. Literally. Other than the data recorders, avionics boards for spacecraft and satellites were also shake tested. The whole thing was driven with an old IBM PS/2 machine with the glorious and legendary Model M clicky keyboard.
Knew it was a motor of some sort, but not what it was exactly. Interesting. There must be a lot of standard test gear we have no idea about.
That's a heck of a massaging device , you can massage of a playlist!
We have a very simple yet expensive engine start tool for truck APUs, for maintenance, it's 500$ and they don't secure the voltage regulator, after a short amount of time it snapped off, had to get a new tool, I open the new one, same thing, I had to use 5$ silicone to secure it.
We used one of these with a similar rubber membrane/ tube interface. It was for testing the consumables for urology diagnostic catheters.
That setup would make a powerful electrolarynx.
These are cool. Combined with high speed imaging and Euler filtering, small oscillations can be amplified to see minute motion in an assembly, helping to identify potential modes of failure without destructive testing!
A strobe too.
i would love to see that regulator under vibration, under thermal camera. Im wondering if its legs are warming up from material fatigue
Fascinating! I have two of these in my shop - bought off eBay for $5-10 each a few years back. They were made by Griffin George for use in schools in the UK, for wave table and plates-with-salt experiments. Time to dig them out I think....
We got a board back from testing that had inner layers delaminated
fixed it with a metric assload of vias
In refection to unusual devices we see today called "acoustic transducers" which are basically a speaker driver minus the speaker cone . in this case they attach a heavy physical mass to the electromagnetic driver coil feed it the bass signal from LBE channel of a multi track audio film , then the device is mounted to chair you sit in so that the viewer can feel the LBE effects in the film and you don't drive the neighbors insane by playing a sub woofer at high levels .. A number of 4D cinemas like Disney's Avatar, flight of passage use this technology to make the experience more immersive , I do realize the device your showing , apply s the frequency directly to the object being tested instead for example testing a circut board being used in rockets navigation system that would exposed to all kinds of extreme vibrations for issues with component harmonics.
21:16 little things makes man happy :)
we had 2500 pounders where I worked in the late 1950's. Aviation secondary power systems for military jet aircraft. They had huge permanent magnets. They'd take a 12 inch Crescent wrench out of your hands if you got too close. Water cooled. We used, mostly, dental cement to attach sensors. Epoxy had just been invented, I think. BTW, about half of our test equipment was still vacuum tubes.