6-circuit slip-ring teardown
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- čas přidán 14. 06. 2023
- This is a fairly common item on eBay. The fact it's on eBay does mean it may be a dumpster product, but it's a good indication of what is available from better quality sources.
The electrical spec for this seems a bit zealous, especially when you see what's inside it. I think I'll give passing mains through this a miss. Even the 2A contact rating seems a bit generous.
But the construction actually turned out to be surprisingly good. Not just with two bearings, but a very clean construction with the rings also acting as guides for the sliding contacts.
For beefier applications AliExpress has some very rugged looking slip ring assemblies with carbon brushes and chunky brass rings.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- www.bigclive.com/coffee.htm
This also keeps the channel independent of CZcams's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators - Věda a technologie
We use them to bring power from the body to the dome in R2-style droids. Generally double up the wires for 12v and ground, and drop the voltage to 5v for LEDs and such in the dome, to reduce the current across the slip ring as much as possible. Thanks for taking one apart!
I was going to suggest to double up on wires for most things. ive pulled them out of older VHS players as handy slip connections for projects but those are getting to be rare these days.
How can dropping the voltage reduce current?
Lower voltage does however reduce the pitting if sparking occurs.
I would like to see your Droid
@@1kreature I = U/R, I'd assume. R can't be modified, so all we can reliably change is U.
There is no other choice.
@@1kreature less flow through same space is less flow. If you're starting from 0 and you only need 5, why stress the part to 12?
Bigger question to me is why would you pass higher power through it instead of have the power source in the same container, and run everything else through the ring.
Hey Clive great video, the business i work for in the UK sells a lot of high quality slip rings for industrial use so I might be able to give your readers a little insight into some of the other uses for them. A common use for one of these is in the rotating head of the flow wrapper system that packages sealed plastic wrappers, chocolate bars, crisps etc. The head in these systems rotates very quickly and has high voltage to feed the hot cutter that crimps and separates. The slip ring you had here looks like it would last 5 minuts in an industrial environment, but inside the theory is very similar, this is what we'd call a capsule slip ring and we do sell others that come in 2 parts where the brushes and rings are separate entities. There are indeed slip rings that are good enough for multiple streams of hd video and the best of these units would be present in a lot of radar dish assemblies, missile trackers, satellite solar panel control etc. There are nice beefy slip rings in a lot of places, wind turbines, helicopter propellors, mri machines. The price differential for the hobbisty stuff like you showed and some of the commercial application ones though are mind blowingly high. If you'd be interested in having a look at some of the higher end equipment I think we'd probably be able to arrange that.
Interesting post! Send Clive some bits... Slip rings have so many uses and I think they would be more common with general education reminders.
I do hope Clive takes you up on that offer, it would be interesting to see the similarities and differences!
@@dosgos There are also similar roatary unions for fibre optics (look up FORJ) and rotational fittings for high pressure liquids and gas.
I used to do repairs on dance-club sound systems; occasionally I'd be asked to fix lighting effects that rotated in multiple directions (often Italian-made, ugh) with two or three motors, which I hated working on. The slip-ring assemblies were usually pretty beefy, often having to pass 120 volt mains (US) for the synchronous motors and lighting a bunch of 12 or 24 volt headlight style par-lamps wired in series. When a lamp went out, the disassembly procedure was often arduous and tedious, and finding the dead bulb(s), or a wiring fault,, was a royal pain.
Clive’s community is untouchable! Great info! I am now really into slip rings lmaoo
A couple of my old projects, I used an audio plug as a slip ring -- obviously only usable for a low speed/low current application, but nice and cheap for a costume accessory.
I always remember being amazed my my mums Clairol heated hair brush as you could rotate the cord or spin the brush around on its cord without the cord getting tangled. This was back in the 80’s but I noticed that the design was kept the same for over 2 decades so must have proven to be safe & reliable.
If it was like my mother's curling iron (that she had from late 70s well into the 90s) they used what was essentially a very slightly modified RCA jack/plug. The the cord had a molded hard plastic ring slightly smaller than the handle that fit into a cavity in each ½ of the handle shell to retain it and allow it to rotate. If the dimensions were any different than a true RCA plug I would be surprised. I was shocked that it worked as well as it did.
@@alexlail7481 Modern cordless kettles in 240v land use a connector that looks like a triaxial PL259
@@TheChipmunk2008 okay... that's not a product I envisioned needing the ability to rotate freely and frequently but cool. BTW we also have and use 240v in the USA, albeit at 60Hz
@@TheChipmunk2008 Same design in the US as well.
@@alexlail7481 Yep used to work in the US. The thing there is not the rotation during use (that actually can cause huge damage) but the ability to put the thing down in any orientation
We don’t buy them from eBay but we use slip rings for geophysical winches. These are used to lower measurement tools down drill holes. The winch drum will have (literally) miles of wire rope on it that holds the weight of the equipment and has with conductors up the middle to carry both power and data. Happy to try and find you some (small) junk to pull apart. Our slip rings cope with hundreds and even thousands of volts (to overcome the long skinny power wires)
For Oceanographic research we use a similar arrangement. We also use fiber optic rotary joints for high bandwidth applications. Single pass FORJs are easy to understand, but Multi-pass work via magic.
@@JoshEaton I expect there is probably optic fibre being used in geophysics too but thankfully I’ve not had to deal with it. Fun enough making a termination strong enough to hold a tonne whilst keeping the conductors waterproof.
@@JoshEaton, Fiber optic rotary joints! I had never heard of that being done but I can see why it would be very useful. The alignment of the ends of the fibers must be very critical; or perhaps it's filled with an optical gel as well, or encased in a vacuum?
@@goodun2974 FORJ are typically sealed but not necessarily under vacuum. The alignment is critical, although the use of an expanded beam lens reduces the tolerances a bit.
Most Multi-pass units use a prism rotating at half the speed of the rotor.
Hi, Clive. Nice dismantling. In my job, we use several rotary joins on radars : they have to sustain an enormous amount of turns (around 50M), but not at a high speed (15rpm max). Some uses as much as 21 slip-rings (some of them connected in parallel to improve current when required). They are not coated with gold, but gold is an important part of the alloy used to make them as well as the brushes... The groves are lubricated with a very special oil. Quite expensive when we need to refurbish them every 4 or 5 years!
Rotate and radiate. 🤣
I guess the actual RF Power goes through a wave guide in the center then?
@@DasIllu, you're right. 2WG and 5 coaxial channels. Slip rings are only for AC/DC signal and power.
Interesting! What type of lube is used?
This type of slip ring was used on a clearance dredger I worked on. It transferred data from the crane position, to the ship's bridge, for computer monitoring. It allowed the crane (which was independently powered by diesel) to turn 360 degrees. It worked well, until someone doing maintenance under the crane pedestal, banged their head on it and smashed it. A later modification used a WiFi system instead.
Worth noting that for a lot of the ‘bans’ on heavy metals are for devices intended for consumer use or otherwise mass production. Where you will end up with lots of the unhealthy material in the general environment. With exemptions for situations where there is no other option to meet performance requirements and the usage is so small or limited that it isn’t that much of a danger at a social level. For a related example you have the EU requirement for many devices to use USB-C or USB-C with USB PD. That only applies to a large number of consumer devices but will not cover many more specialised devices. Another example is how you can still buy leaded solder for personal use but it’s banned for commercial production use. Complete difference in scale of damage risk.
I used to play with mercury as a kid. I had (and still have somewhere in a box) a C64 when I was young. Included was a joystick without a base. Just the handle with a cable coming out of it. No buttons or switches except the fire button. 20 years later I decided to open it. Inside was a small PCB with 4 miniature mercury switches. Each quite small and angled in one axis to act as a simple tilt switch.
tbh... except the novelty aspect of having mercury switches in a toy the joystick was quite shit
@TwistedMentat
Yeah, here in France it's still possible for private individuals to get lead based solder, heck even NiCad batteries !
Some drain cleaners however, not anymore !
Why ?
Because of stupid laws !
@@psirvent8 NiCad is still used quite a lot out side the EU in toy battery packs as being more stable than lithium less risk of it injuring a child
@@Hewitt_himself I don't think so, at least not for new toys.
Didn't you mean NiMh instead ?🤔
As far as I'm concerned, NiCad batteries have been out of physical stores since maybe 15 years ago, and stuff like power tools and cordless landlne phones always come with either NiMh or Li-ion battery packs for the former and NiMh cells for the latter.
I've even seen many years back ago articles about the ban of NiCad batteries for ordinary consumers, yet you can still find them on reputable websites.
They don't ask for an ID or a company registration number or any of that business, unlike chemical suppliers whenever a listed chemical is involved (Potassium permanganate, boric, sulfuric and nitric acids, borax, hydrogen peroxide above a certain percentage and so on...)
I had a machine (privately owned by a hobby club unfortunately) that had these mercury slip rings for power transfer, they were worn out and i looked at replacing them. According to the manufacturer who still makes them 60 years down the line they are by EU law only available: 1. as a replacement for existing machinery and 2. only to business customers of course. I bought the exact ones Clive shows off here and they really do seem to work pretty well, i never had the chance to see how they work over time though since the hobby room where the machine stood was closed down.
Nice Video Clive. The last place I worked they had mercury whetted slip rings. I ran into a problem with one of 50 of their machines, realized it was the slip rings and was told in no certain terms that I was wrong - one had never been bad in 25 years. They were computer signal wires, that perplexed me as to how a sensitive signal that went to an analog input of a microprocessor. Went against management, and pulled it anyway - buried in the heart of the machine. Found that a mechanic crow-barred a bearing off below it, cracked the plastic, and the mercury leaked out. After it fixed the problem, every call they got turned into a change the slip rings call. 🙄 Managers🙄
Place I worked before that had a run-in rack (Burn in brush seater) for 'sweeper' motors (Hoover). They put 51 motors in a merry-go-round, using a 17 neutral rings for the 3 phase 4 wire 110 volt system. 51 power + 17 neutral = 68 rings / wires in a single center pipe) Each pulled 9 amps. These all fed from the floor thru a center pipe / slip ring array.
They came out with a new, more powerful 14.5 amp motor, and I told them, "Too much total current for them all to run up that 2.5" center pipe - it will overheat." The pipe was already so hot that in had melted the plastic top cap to keep fingers out. "NOPE! You're wrong ... the 3 phase current will cancel out in the pipe!" Got a call that night ... melted the whole stack. Spent 16-1/2 hours rewiring it with all Teflon wire.
Did it's sister rack, 2 days later ... 14-1/2 hours. I guess there must be a heat coefficient ... especially when all the wires come up through the center, and then go down the outside to slip rings, that are spaced 1" apart, so there is a 5' difference in length difference in the current cancelling, magnetic flux around the pipe, between the shortest and longest. The only good thing is, they got me outta' bed, I didn't bring a lunch, and they refused to say over the phone why they needed me - so they brought me pizza, and sat it beside me to work😛
My grandfather used to manage the slip ring factory in New Jersey (5th Dimension). Gold rings bonded with lasers and tiny balls of iridium. Used for D4s
"Slip Kid, Slip Kid, second generation/ I was a *solderer* [sic] at 13/ Slip Kid, Slip Kid, realization/ there's no easy way to be free/ no easy way to be free...." paraphrasing from the Who
Use them all the time in the hobby of modelling fairground rides. Gets 12v power across articulating parts just fine.
More useful are the "hole" kind, wider and donut shaped, which fit around an active drive shaft
At school in the 90s i made my own slip ring for a wind turbine using lathe machined nylon with copper brushes for 2 terminals
Our vacuum cleaner handle has a larger version of this to pass power to the powered beater brush. Have had to open up and clean contacts over the years when operation has been intermittant. Thanks for the detailed breakdown Big Clive
omg im stupid. just yesterday i started thinking about how this could work and till now i couldnt for the life of me figure out how it could work...
but the timing of this vid was perfect
Thank you Clive.
I've used these to fully mechanise and light an Airfix dockside crane, controlled wirelessly from a DCC controller. 😀
Since I was a child I've wondered how electricity was transmitted through a rotating joint. This is awesome, thank you!
it's always awesome
Ever see or hear a rotating Leslie speaker, the type often used with (electronic) church organs and occasionally by guitar players? (SRV did). The low frequency speaker typically doesn't rotate and instead has a slotted baffle enclosure around it ( a "cheesewheel") that rotates, and so sliprings arent generally necessary for that, but if the speaker cabinet contains high frequency horns that rotate, the audio signal to the horns would have to pass through sliprings. (A Hammond B3 organ through a Leslie speaker, in the hands of someone who really knows how to work it, is a massive wall of sound that'll just about make you levitate).
The most gorgeous slip-ring that I ever laid my eyes on was on a project several years ago to restore an 18m satellite dish built in the late 1950s. Signals and power (lots of power) were brought across the azimith-axis interface with a 32-channel slip-ring where the rings were solid brass, with phenolic separator sheets. The contacts were brass rollers that rode the brass rings. It was a lovely, lovely piece of old-world engineering....
Where I work, we use tons of slip rings for various things. In fact, we have some fiber optic sliprings for data. That is a teardown I'd love to see.
I've seen a single fiber run straight down the middle of a rotary joint, but when you say slip-rings, are you implying multiple fibers? Now I'm intrigued.
@@myself248No -- that's what I mean also. It's a combination electrical slip ring with a fiber in the center. I should have been more clear.
Looks like a neat parts-bin bit for RC stuff like robots and scale vehicles with various turrets as well as giving a bit more freedom of movement to FPV cameras. Nothing where you'd put much current through though, given that gauge.
This type of slip ring was used in an industrial product I worked on a few years ago. We life-tested several to determine service life as the manufacturer was a bit vague about that. The life was quite long, multiple hundreds of millions of revolutions at the rated max speed (a few hundred rpm) passing 250 mA. Afterward they were tested at thousands of rpm to evaluate the abuse case and contacts life was better than expected. Problems did arise though in mechanical damage to bearings and plastic parts over time at higher than rated max speed , mostly due to imbalance and creep of the plastic parts. I'd have no hesitation using them for rated speed or lower speed operation at rated current - but low voltage only - not line voltage. BTW as of a few years ago I understand mercury slip rings are still used for very high current applications in shipboard cranes inside the slew rings. Cheers!
I was expecting pogo pins inside to maintain a constant pressure against the core.
Interesting teardown. Thanks Clive!
I expected springy contact blades stamped out of flat spring steel and electroplated with a more durable material .
All of the cctv rotators I've worked with send the signals for cameras through these with no problems. Are also available with more than 6 connections, have some with20 plus.
I've been looking for a video capable slip ring to make a custom camera "rig". I literally can't find any (well i only found 1 manufacturer), do you know if they have a specific name?
If you don't actually need constant rotation but do need 360deg coverage automotive airbag " clock springs" are an option.
@@Ubya_ just send Ethernet over the slip ring, this thing probably works fine for 100 Mbit.
Modern cameras are generally ip connection. That is power over Ethernet, or Ethernet and separate power. Effectively only 6 connections needed, Tx pair, Rx pair, DC +, DC -.
@@mrfrenzy. i'm using hdmi since it is a rig for a normal camera
Might be fun to get a few of these to test different uses like low power or data or something.
I haven't had a requirement for these kind of slip rings, but I did finally get around to buying some teflon coated wire, and I really like it. Obviously not as easy to strip as the regular PVC coated wire, but it's nice when it doesn't melt back when you tin the ends of the wire.
Beware thar Teflon is a PFAS with associated dangers .
Yesterday, I was thinking "Hope BC takes apart a slip-ring", and here we are! How odd is that?!
If I had known what I think could come true, I would've thought about having a million bucks.
I have the same one on my weather vane project. I have an Arduino Pro Mini inside the rotatable 3D printed weather vane body, a propeller on one end, a MLX90316KDC-BDG rotary hall direction encoder in the middle, and a tail fin at the back. The Arduino processes the data and comes out via serial RS-485 through the slip rings to an indoor LCD display. The slip rings have been working fine for a few years now. Nice to see how the slip rings work inside, thanks.
I've several of those pulled from scrapped PTZ cameras.
They've been fun to play around with.
This device would have a multitude of applications for model railroaders and diorama builders. Railroad turntables, fairground carousels. etc.
Thanks for sharing. Brilliant video Clive.
Have used above Slip Ring in a Model Railway Turntable very successfully. DCC working perfectly. With a quality Gear Motor, Gear Box with a Worm Gear (acts as a brake when stationery) turning a Quality Pulley Wheel (with industrial rubber belt fitted to it) making contact to a larger Platter (with industrial rubber belt fitted to it & mounted to the TT Shaft). Both Rubber surfaces making contact (no slipping) and therefore no noise transfer makes for super quiet operation. Have mounted the whole Gear Motor (DCC Decoder controlled) & Gear Box to a Swinging Mounting with the Pivot Point using a press fitted Bearing with a Spring keeping tension to the Large Platter. This giving a clutch-like feature. Have had much interest as to how it works, given its all been built inside of a display box, wall power, Transformer with fuse, Digitrax Unit etc out of sight...
I worked with some such when I worked at Briggs & Stratton running engineering tests the ones we used where much higher quality but were expected to perform at much higher RPM.
Fun lil thing it is
Same principle at play with regular corded vacuum cleaners, the kind that has a windy cord that you need to pull out and then it reels itself back in when you hold a button. The fingers in the mechanism get worn out over time, it's a very easy fix as you just need to put a bit more bend to them.
At the casino I work for, these are used in rotating sinage to carry data for video and DMX lighting.
Considering that they are spinning 24 hours and 365 days a year, they are surprisingly reliable!
Tripped me out when you pulled those bearings magically out of the image
These are used all the time in CCTV, they transfer both video, power, serial, ethernet. Though the ones i've extracted seems to be a little more fancy and have 8-10 wires.
Hi Clive. I made my own tether winder for my ROV using one of these. And yes its only signal only that I use. Interesting to see the guts of one. Very simple. Thanks.
I used to build transmission electronics for video camera modules that would receive the 24-36V DC along with the HD component signal over a custom-made 3-line disc rotary contact. The cylindrical stock contacts would not be able to transmit the signal reliably. We had only one manufacturer that could deliver a constant enough quality and durability - and they did cost a pretty penny too.
The cord winder in a vacuum cleaner has a fairly beefy slip ring (usually 2 pole) if anyone needs to supply mains to something rotatey.
I'm sure that if I purchased one then I'd find a use for it!
If your use-case can't tolerate the rotation speed limits or possible drop-outs of slip rings, these days it's also possible to assemble solutions that use inductive power transfer with two coil rings (the field doesn't care that it's rotating in-plane) plus a wireless communication mechanism for the data side. At its simplest this can mean co-opting a Qi charging transmitter/receiver plus connecting to the widget on the rotating bit via wifi, but various solutions exist depending on your power levels and data transfer requirements.
A bit more complicated than slip rings, but sometimes an entirely sealed "no sliding/moving parts" (except the rotating shaft itself) design is preferred.
The commonly used rotating LiDAR sensors, e.g. on robot vacuums, use a combination of inductive coils for power transfer to the sensor inside the rotating head (rotation is typically achieved by an external motor with a belt or with a direct drive motor underneath) and infrared for bidirectional data right in the center.
that's how video tape helical scan heads work, except they just use the rotary transformer for data
I found it interesting that CT scanners utilized slip rings, really large ones with carbon brushes when VCRs moved to rotating or rotary transformers.
considering the crazy magnetic fields in play, rotary transformers may have been a bit of a challenge in a CT
@@askjacobYou’re thinking of MRIs, CT scanners typically use X-rays.
An X-ray tube needs DC to work, they maybe didn't want to squeeze components for rectification and smoothing into the scan head. Also how much of a headache is it to place a rotary transformer far enough outside the axis of rotation to be useful? Leaving enough space for the patient requires a considerable opening in the middle.
@@askjacob The large magnetic field in a MRI machine is static (DC), so it wouldn't affect air-core transformers. There are smaller AC fields and RF pulses.
The cctv application will be just fine because image signsl stability is only really important when stationery anyway
Hammond organs are often connected Leslie speakers that have rotating speakers. Leslie speakers units use Mercotac bearings which contact the amplifier to the revolving speakers.
As I was typing about mercury slip ring sets, you said exactly that.
Finally, something for adding backlights and like on Polish toilets
I used one to repair a fantec sim racing steering wheel when the ribbon cable got cut after constant use over time. Worked great and is still in use.
I have been using wind turbines for around 6 years, and they come fitted with non sealed internal brushes and slip rings which fail after 12 months or so. I fitted a mercury wetted sealed unit with brings down power and data to my controller and it performs perfectly (now 3 years without trouble). They are very expensive, especially the high current versions, but save 2 days of ladders and pulling apart everything to replace the factory fitted open units.
The old 1/4" headphone jack works as a crude slip ring.
I would imagine a 3.5mm (1/8") jack could work too, with the possibility of 4 pole variants also.
I did that in the past too. Not sure how many rotations it would handle. A dab of grease could improve that.
Thank you for this interesting video BC. In the past, I've used stereo jack plugs and sockets for low voltage low current rotary connections.
Thanks! Have used one of these with great success in a kinetic sand sculpture. Very reliable 👍
So That's how; Well explained. ... _but what do i know._ Thanks Clive!
After Reading some comments below, seems i've missed a lot of classes. Much I've failed to see, till now.
I made slip ring thing pings myself using stainless steel rings and carbon brushes to drive HPS lamps for the hobby. The rotating thing ping apparatus was physically set in motion by an old clock. Pretty amazing that it worked out. Actually the ballasts were separate so also the initial starting current went through my slip rings. Never had any problems.
I use these on my Planetarium Star Projector. There is an axis for rotation at the base /Yaw with 48 Conductor rings, another axis for Elevation with 2 sets of twelve on both sides, and then inside for the Diurnal I had to hand build an 8 conductor pancake slip ring. All these carry the grounds, stepper motor voltages, encoder signals, and control voltages to turn things on and off.
I have a few of those and was wondering how they worked. Now I know. Thanks B.C.
i've made a hobby project in the past with one of these for an ethernet cable. used it with laptop on one end and raspberry pi with camera on the other. worked fine.
On the CCTV side, they are used in PTZ cameras to pass the ethernet connection and power between the rotating camera portion to the fixed power/data input section.
Great video. We had a problem to solve at work when we wanted a slip ring to carry high frequency signals..
I replace them pretty often in PTZ CCTV cameras
heavy man ! Clive i commented about the package given to me which poured mercury from broken slip rings once opened " dont know what in it but its fffing heavy" the storeman exclaimed.
Very interesting. Thanks for the breakdown.
*Thank You* Clive, that was quite interesting. Much appreciated. 👍
I remember seeing these for phone handsets when I was little. They seemed like magic.
This video couldn't be more on time, I bought two of these and received them yesterday. I was curious as to how they where working inside :)
I've always wondered how they worked and I should have guessed, so simple and complex at the same time (to me). I pretty much assumed it was magic of some sort 😉
I see easily its application in a wind speed measurement installation. quite handy to have a couple of these around 😊
These are essential for your RC Tank turrets.
US Navy SH/MH Seahawk helicopters use slip rings at the tail rotor (for blade de-ice) and main rotor head (blade de-ice, position sensors and blade fold motors) and while the tail rotor slip ring is 'race tracks' of copper and pickups of sprung carbon contacts, the main rotor is a 3+ foot long monster that travels the entire length from the top of the rotor head and the distribution box, to the bottom of the main transmission and even then the cable for it is another 4 feet long.
I was here to mention the "wetted" slip rings. Used them for analog camera systems that had to reliably carry the signal and quite a bit of power to run the thing. Neat!
Like the Roundshot? Or do you mean a controllable camera mount?
@@mjmdiver1137
It was a camera for a sewer snake that would spin the wire on and off of a big reel while sending composite video through it. It had to run the camera and lights at a minimum. Some models had full pan and tilt and tracks or wheels to propel them.
In the 70s, some Leslie speakers (the ones with the speaker actually IN the drum - vile) used Mercotac mercury contacts to get the signal into the speaker. Not always that reliable. The service advice was "remove the capsule and shake it to get the blob of mercury back into position". Always made me feel like James bloody Herriot about to take a cow's temperature.
Most newer cars do not use slip rings to signal from the steering wheel to the rest of the wiring. They use a long strip of flexible printed circuit board to wind and unwind around the steering column as the wheel is turned. Of course this is limited by the number of wraps that can be made but steering wheels also have limited turns. It works well and gives glitch free operation for even high speed digital streams. The robustness, noise forgiveness, and redundant wires of canbus are not necessary with such a clock spring type arrangement.
Slip rings were used in the F-111 and C-130 artificial horizons (ADI) when I repaired those in the '90s.
They would feed the pitch and yaw motors that were inside the spheres.
I've had success running a USB 2.0 video feed over cheap Aliexpress slip rings like this before. At the same time, I've passed 24V power and step/direction signals for a stepper motor driver. In the limited testing I did, there were no signal dropouts.
I just changed my design for a hover control experiment that I'm building, just because this simple device isn't available locally, and Ebay takes a month to deliver anything to here. it's very interesting to see the inside of the, I'm now thinking of making my own make-shift version
Aliexpress has them for RC excavators to transfer power to the "brushless" motors that drive the tracks for walking the machine.
It's interesting that you mentioned that they used to have some of those that were Mercury wetted. I didn't know that but for years I have been wetting my ham radio antenna connections because I get a stronger signal and I have done it to a few audio connections between the amp and speakers on my home theater. I did not notice a difference on the audio but There is a measurable difference on the antennas and coax Both when receiving very weak signals and when transmitting very high wattage
Contact shape is critical for high frequencies because of the distribution of currents. The skin effect produces drastically worse conductor performance around "pointy" features, and wetting can physically round off those conductive shapes. Looking at cut-away SMA connectors was a real eye-opener for me... the pin specifically mates in a ring, keeping cylindrical continuity, while the shield is lapped in its own recess, held flush by the screw. A circular profile in both cases is kept continuous, never opening into a "C" or flattening out.
The FRC team I mentored a few years ago was even able to run CAN bus over these, I was quite surprised that it worked.
Edit: iirc we could run 12V at 40A on the model we ran, and CAN on the remaining two pins to the motor controller. We put the motor controller on the "far" side of the ring because from memory there were some encoders connected to the controller and it was simpler to run just 4 wires thru the slip ring.
Hey mine too. 16 bomb squad and 323 lights out! #datswerve
What speed CAN bus? I can see some of the lower speed versions being fine, but I'd be wary of running a 5Mbit/s CAN-FD link over a slip ring.
A company I worked for in the 90's ran a 10Mbit/s transputer link through a slip ring connection, and we had to add extra error checking & correction to the protocol given the noisiness of the link.
@@markbooth3066 Just took a look at some forum posts about the controller, it appears to be a 1Mbps bus speed. It may be capable of being able to negotiate down to 250kbps too.
@@carneeki sounds almost like a physical zigbee/z-wave, they can drop down depending on the quality of the data link, I can imagine things over a sliding contact could get dirty as regards signal. CANBUS getting a little bit too pervasive, trying to make things impossible to repair, when we need to repair as much as we can..
PTZ Cameras run audio, microphone and CAT5 Ethernet trough these things. Crazy stuff
Now that looks perfect for a model railway turntable using DCC (Digital) rather than the peco split copper track and sprungloaded pins. Brilliant.
A slip ring circuit. Didn't know what they were called. I wanted to do a cucoloris train window effect for a show and was wracking my brain with all manner of battery/bearing constrcutions, and it was this i wanted.
I used a similar one to enable 360' rotation on my 1/16 scale Challenger 2 tank :)
I have always wanted to look inside these things!
I remember taking apart a vcr when I was younger and when taking apart the spining head, was fascinated to discover not a brushed slipring, as I had presumed, but a contactless one. It used a series of flat concentric coils on each half to couple the signal from the magnetic pickups from the fast spinning head to the fixed body of the machine. Quite a eye opener to me at the time.
Heh... I took apart my fair share of VCRs and only learned how those inductive rings worked some 20+yr later. amazing, really... such tiny signals!
Id love to retrofit one into my aftermarket steeing column for steering wheel control buttons
The 250v is rated based on insulation and sparking that could occur inside. If its 24awg max amps is .5 but you should be lower than that fir safety. You can run 250v if its limited to say 200ma or so.
Nice!
Though it looks like it should be rated 22V 200mA instead, doesn't it?
You're always on the safe side when you divide Chinese numbers by 10. Same with accu capacities...
Car stereo watts, the number of people a tent can accommodate, the number of hours an LED fixture will work for... all closer with a zero lopped off.
Our AGV track wheel casters use these to pass the data from the wheel mounted optical encoder to the processor. In this application the track wheel is used to to confirm speed and distance. There is a second encoder (without sliprings) on the caster assembly used to confirm the casters angle. The caster needs to be able to turn 360 degrees when the vehicle is reversed.
When I used to turn wrenches on M1A1 battle tanks for a living, I once performed a forensic disassembly on a malfunctioning turret slip ring (it also passed hydraulics in addition to electrical current and signals). It was nothing like the one you took apart (the electrical connections passed through a pair of platters instead of a cylinder).
According to Wikipedia, that is in fact a commonly used alternative design. It suffers from a bunch of reliability issues, but it has the advantage of being flat and increasing in radial dimension as you increase the number of conductors. For some applications, that's a crucial difference, as you can't arbitrarily increase the length along the axis.
We used to use ARBs. (Amber rotating beacons). Mostly the domain of the poles and holes guys but some bright spark thought hanging them on ladders would be a good idea too. They were great. Not lit up and flashing but you could break the mech and recover a great very robust electric motor, one of those spinamathings and a flasher. They also gave us access to those expensive big square batteries with springs, they would run a radio for months
Rotating laser levels that shoot a reference line onto walls for installation of drop ceilings must contain a set of sliprings....
@@goodun2974 ...or just a rotating mirror assembly that needs no power ;)
@@NiyaKouya , Perhaps, but if you really need near perfect alignment, Which would be easier to align perfectly, the laser itself, or the mirror that has to reflect it? In order to spin a mirror and have the laser beam stationary yet reflect 360ﾟ all around so that it puts a level line on all 4 walls, I would think it might be easier to spin the laser. The mirror might have to be some kind of weird mirror ball in order to do this. Or perhaps it would require a prism or a fiber optic link or something like that.....
Nice to see the innards of these sliprings❤👍. Could have a number of interesting uses such as various kinds of diy generators(handcrank, wind), rotary molders with precise stepper control and some other exotic applications...🤐. Just some 💭
I think CT scanners use optical slip rings for data connections, wild tech
That's interesting, my idea for such a contraption would be closer to motor brushes gliding along a series of concentric rings. This is much closer to something like a headphone plug and jack, which is probably better.
Your intuition is absolutely used in industry as well, where applicable, the main advantage here is keeping the contacts at the same linear speed. Another similar example of a flat, concentric device would be the rotary transformer in a VCR, that connects the spinning tape head.
The cotton candy machine I work on at work has brushes on a solid core of copper that is attached to brushless motor. These are the connections for the heating element that spins. It's a pretty old machine so I'm sure that later revisions have been updated
That's very standard. Two brass or copper rings with two carbon brushes.
Hi!
Used a lot in rc tank turret 360 rotation, you can get them up to 24 wires!
I have a different brand of these slip wrings for a wind turbine project that is on hold. The wires coming through the model I have are much more substantial as the turbine can put out about 1500W 3-phase 110V in a 14mph wind.
I used one of these for a wind vane data transfer from a digital compass, works OK
You only really need these for continuous rotation so it's not too hard to avoid having to use them, usually. I used them once but the product we were developing didn't make it to market in that form. Happens more often than you'd think.
If higher current is required, Sandia Labs recently took out a patent for one of these without the use of sliding contacts. Imagine the inside of a car diff, but with a conductive belt drive instead of gears. I imagine it works quite well.
If you're not familiar with them, look up automotive clockspring. It's a clever way of making electrical connection to something that makes a limited number of turns, such as a steering wheel.
I took one apart in a video.
I found one of these with mercury wetted contacts in my stash from an old project I had forgotten about. Three contacts for ground, power and data.
i just commented on this. the lack of the good stuff.
hang onto it because they are becoming scarce!
and trust me, that thing will still be making perfect contact after 20million cycles.
Ironic that removing mercury would make the switches more mercurial.
Can’t recall, but it was one of their longest life rated unit with 10’s of millions of rotations as you said, with sealed ball bearings in all metal housing.
It was for a rotary LED music visualizer project. I ended up not using it for inductive power transfer and IR LEDs to transmit the data to receivers on the spinning PCBs. Because it was quite expensive and not realistic if the device ever went into production.
It never went to production as trying to balance the large three armed rotor at nearly 1000 rpm was too much of a nuisance.
Funny how I find it a month ago and Clive does a tear down on similar device! 😀
I need to make something with it….
@@gavincurtis now i look again, they arent that bad on the pocket. not as uncommon as they seemed to be a few years ago...
or maybe i just wanted too many connections. iunno.
Still would like to have seen 240V through it. Always happy to see electrical carnage.
A slightly bigger version is commonly used to upgrade motorcycle wiring on the front fork because the wiring from the factory bends every time the front handle/fork is turned and eventually breaks the fixed wires.
I've never seen a motorcycle with a slip ring. I've never had a motorcycle that had handlebars that turned 360 degrees either... Stunt bikes maybe...
the teeny tiny baby version of what is often used in fairground rides to transmit actual power to lights and motors on moving elements, especially on the more complex carousel style rides with individually moving gondolas. I still wonder how they used to synchronize all the light effects on older rides, either through individual controllers and sync pulses or with just many more contacts for the light effect channels?
It's possible that the power was modulated with a clock signal and that was used to keep individual controllers in sync?
Either one slip ring per channel, or just power and a controller on each car with a simple chase.
I work on large Komatsu (formerly P&H) electric rope mining shovels (think really big excavator, as in the size of a small apartment building...) which use an extremely large version of this that is about 8 feet tall and weighs about about 1000 pounds that carries everything from 7200v supply down to 24v control signals, even compressed air and high pressure grease and open-gear lubricant between the crawler section and revolving deck and machinery house of the machine...
That really is similar to a stereo jack. For a CCTV, you might be able to just use a stereo plug and the jack as a sort of slip-ring. I think I've seen some cameras that are constantly rotating and those probably use something like this.