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!

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.

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.

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.

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!

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)

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.

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😛

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....

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

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.

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

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.

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

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. 😀

I was expecting pogo pins inside to maintain a constant pressure against the core. Interesting teardown. Thanks Clive!

Since I was a child I've wondered how electricity was transmitted through a rotating joint. This is awesome, thank you!

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!

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.

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 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.

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.

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

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.

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.

Might be fun to get a few of these to test different uses like low power or data or something.

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.

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 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.

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.

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.

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!

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

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 found it interesting that CT scanners utilized slip rings, really large ones with carbon brushes when VCRs moved to rotating or rotary transformers.

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.

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've several of those pulled from scrapped PTZ cameras. They've been fun to play around with.

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

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.

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.

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.

Tripped me out when you pulled those bearings magically out of the image

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

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.

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!

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 😉

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'm sure that if I purchased one then I'd find a use for it!

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.

630am nursing my coffee at my work bench I read the title as 6 circuit slurring teardown , that's completely possible 😂🤪

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.

Great video. We had a problem to solve at work when we wanted a slip ring to carry high frequency signals..

As I was typing about mercury slip ring sets, you said exactly that.

Thanks! Have used one of these with great success in a kinetic sand sculpture. Very reliable 👍

I used one of these for a wind vane data transfer from a digital compass, works OK

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.

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.

I have used several of these when I built my robot, one in my robot head/neck, one in its torso to enable those parts to rotate constantly. I am using one now in my current project. They where a lot cheaper when I bought them. (Pre Covid)

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 remember seeing these for phone handsets when I was little. They seemed like magic.

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

Id love to retrofit one into my aftermarket steeing column for steering wheel control buttons

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.

I see easily its application in a wind speed measurement installation. quite handy to have a couple of these around 😊

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 have a few of those and was wondering how they worked. Now I know. Thanks B.C.

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).

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.

Finally, something for adding backlights and like on Polish toilets

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.

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 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.

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'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.

Gosh darn it Clive I just fell in love. lol. I have a special love for this apparatus. I have autism and have taken things apart since I was 3. I visualize the function of everything and this is a piece I have yet to see in this state. Thank you

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.

These are essential for your RC Tank turrets.

I paused the video at the start thinking "how on earth can that even be possible?" and drew some diagrams. My alien UFO tech notepad solution ended up being way more complicated than the actual thing, but I believe both would work. 😂

Now that looks perfect for a model railway turntable using DCC (Digital) rather than the peco split copper track and sprungloaded pins. Brilliant.

That's pretty neat. It must be how R2D2's head works. LOL Now I wonder about the special machine that makes them.

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.

Aliexpress has them for RC excavators to transfer power to the "brushless" motors that drive the tracks for walking the machine.

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.

click on one, click on two and we got this open 😂

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.

Another case of "any sufficiently advanced technology is indistinguishable from magic".

Very interesting. Thanks for the breakdown.

I have always wanted to look inside these things!

Modern cars typically have clocksprings instead of sliprings, because they have more wires (ie: horn, airbag, radio controls, etc). When I removed the airbag, radio controls, & replaced the OE wheel I needed something for the horn… So, I made my own slipring out of random shit, including a floormat. It didn't look good, but it was hidden, and it worked 😊

*Thank You* Clive, that was quite interesting. Much appreciated. 👍

Nice! Though it looks like it should be rated 22V 200mA instead, doesn't it?

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?

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 replace them pretty often in PTZ CCTV cameras

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 looks like it would be perfect for hobby robotics, some RC servos and liner actuators and a complex articulated device would be easy to build.

I think CT scanners use optical slip rings for data connections, wild tech

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.