The first time I saw this motor construction was a pond water pump. I was so used to a commutator based motor that I thought the complete isolation of the moving parts was some kind of magic/witchcraft. A couple of minutes with an angle grinder set me straight. "With an angle grinder" are probably words for life
The little pump in the cat water fountain and the slightly bigger pump under the washing machine work that way here, though without the multi phase/ stepper engineering. Simple. When the seals fail both will work for a while, until the vibrating rust cuts through the enamel on the magnet wire in too many places.
Clive has given us a view that even us technical guys have seldom seen. It's truly amazing how these small but important control mechanisms work to make our everyday lives easier. Thank you so much, Sir!
I love your show! When I was a child my mother would buy "sacrificial appliances" at yard sales to protect her good small appliances from my curiosity. It blows my mind that you have almost a million people watching you take stuff apart! Keep showing us! Curious viewers want to know!
A lot of the channel viewers took their toys and random appliances apart when they were kids. It seems that Mother Nature designates some of use as engineers from birth.
@@bigclivedotcom At a very coarse approximation I think it might boil down to a brain that is a) deeply curious and b) wired to prefer interacting with inert thins rather than other people. And yes I do think both of those manifest basically from birth.
This interests me quite a lot because I work on older refrigeration equipment, extensively. This is quite the bit of engineering, and totally something I hope never to have in anything I own. There are much simpler and more robust ways to have a fridge and freezer operate off the same compressor. I can imagine the fate of the plastic gears when the condenser fan fails and this is presented with extremely hot gas; or how it works after a few years of service and crystalized POE oil ends up in the working bits. The manufacturer will make some small change to the design and discontinue the prior part, rendering the whole refrigerator landfill fodder with no alternative parts available. In spite of my negative comment, I love seeing how you analyze things and explain them. I really do appreciate it! Just dissing on the issues we are facing with consumer products in general.
Whenever you are about to use violence to open something and do a jump cut, I half expect the next scene to have blood everywhere, your fingers covered in band aids, your bench still smouldering and the ambient flashing of blue lights outside 😀😀
Some of them do it completely differently: ours at home just has the evaporator at the freezer side, and a valve that closes down the air path to the fridge. When the fridge is cold enough already but the freezer is not yet, it closes the valve and keeps cooling the freezer. When it needs to cool down the fridge, it opens the flap valve so air circulates there, and cools both sides. If the freezer is too cold but the fridge isn't cold enough yet, it only circulates the air, without turning the compressor on at all, just trading heat between upper and lower sections (fridge and freezer).
@@Kalvinjj @Kalvinjj neat! If you continue following that logic, you could also omit the valve completely by using a reversible centrifugal fan: if it spins, say, clockwise, it sends the air through both the freezer and the fridge; If it spins anti-clockwise, it sends the air through a shortcut, circulating it in the freezer, only.
The best way to do that is to use some magnetically responsive film and lay it between the two coils (without the drive components), and then step the motor bit by bit to show the fields flipping around.
Check out 'Brushless DC Motors and Brushed DC Motors explained - BLDC Fan (2)' by Post Apocalyptic Inventor. It's an old video but 10 minutes in he shows how to get a compass moving with 2 electromagnets and a switch. A very rudimentary start on how things work. A stepper motor is a specialized BLDC motor.
I'm pretty sure you could find an animated explanation online, but if I try to put a link here that isn't to youtube or wikipedia, youtube will silently delete my comment, so you get to google it yourself. Basically those little metal triangular "fingers" conduct the magnetic field from the coil to just outside the rotor. As you change the polarity of both coils, you move the rotor over one step each time. It's like a regular motor, but with way more poles, and because there are so many poles, you need the fingers to get the field to the right place, as opposed to having individual coils wrapped around the stator.
@@gorak9000 I know what you mean about YT deleting comments. I ALWAYS copy before posting, and then do a refresh, because SO many times I write a thoughtful comment, just to find YT has deleted it. I have experimented and normally it is an external web address or perceived to be a link that gets it killed, but a number of times not sure, but VERY frustrating.
@@BrilliantDesignOnline It's worth checking from another browser also, where you're not logged in. I've had one recently look fine, but then "not be there" when checked sans my login. Quotes there because there's a name for that, but I'm avoiding the same frustration here.
Ah, you reminded me of the unmistakable "clankclankclankclank" of a lighting rig full of Goldenscan HPEs all homing their stepper motors after switch on.
Surprised at how small the ports are, thought they'd hinder the flow of the liquid refrigerant. I guess the flow of liquid is miniscule with the much smaller amounts of refrigerant involved in domestic fridge freezers, especially with R600a which is usually less than 100 grams 🙂
I had a fridge with a freezer compartment in my cottage, and I noticed that when it got very cold in the winter (the cottage was not heated), the contents of the freezer would defrost. I surmised that it was because the fridge basically stopped at ambient temperatures under 5C, and your video just confirmed that.
This is a problem with combined fridge/freezers that don't have this valve (or two separate compressors) and just one thermostat in the fridge compartment. They assume normal room temperature because then the fridge secetion will heat up enough so that the thermostat in the fridge will turn on the compressor. If the room tempertaure is not enough to heat up the fridge section (in a cold garage in winter etc) then often there is a semi hidden switch which will run the light bulb in the fridge section continously at half power (simple diode in series). This will generate enough heat to cycle the thermostat and keep the freezer section frozen.
Fascinating, thanks! Would love more of these teardowns of common household gizmos as we use them every day and have no idea what goes into them. I can see a common failure mode in this type of valve in that the electronics wouldn't know how fast the valve turns as such, so if it becomes sticky it may turn to the start position but then not be able to fully open unless there's extra electronics to count how many turns the motor needs to go from one stop to the other.
There isnt really a way for it to become sticky. The gears operate in liquid R600a which would clean off anything sticky that isnt going to be within the refrigeration circuit to begin with as that would kill the compressor.
Now you need to track down, and disassemble, the driver board that controls the motor. Guessing at least two temperature sensors for fridge and freezer as input.
I'm glad I retired out of the appliance repair business. started in '81 and the closet thing I saw in my time is 50's and 60' refrigerators with hot gas defrost which had magnetic valve that diverted hot gas to the evaporator, basically like a heat pump. tis is a very interesting system, there are two types of systems with the split evaporators, Parallel cycle and TDM cycle , I'll let you young folks go from there, thanks for the video. interesting the advances in the trade
the "multiple windings slightly out of phase" concept is also used for launched roller coasters, where linear stators are placed on the track and simultaneously attract and repel the permanent magnets on the underside of the trains due to there being multiple coils (usually 3) inside each assembly. the train essentially "rides inside" the sine wave generated by the stators, and then you vary the frequency to accelerate or decelerate. it's neat to see something similar in a different form factor!
Sine wave! Of course! Was mulling over a custom linear actuator system design and assumed I would have to make a custom firing order for each coil but sine wave implementation is so much easier. To be fair it was just food for thought about a possible future project, nothing I had actually looked in to.
@@PseudoEmpathy make sure you grab a bunch of accurate hall effect sensors as well, and some type of high frequency reading device (an inexpensive PLC with a high frequency IO module would do the trick). if the Eddy current frequency between the permanent magnets and the stator coils is off by even the slightest amount, you will end up braking instead of accelerating however, this also has the secondary benefit of the stators acting as brakes by default - so if you need to stop the thing, just cut the power and the stators will do 95% of the stoppage for you (Eddy current brakes cannot completely stop a moving load).
I've found them very reliable unless you heat them up too much when you're brazing them in. I've looked at the PCB a little. Looks like they short the 12-14v rail to ground through the windings with IGBT. When you plug the machine in you can feel or hear the rotor hit the home position repeatedly.
Yep! When plugged in initially, the motherboard will turn on a series of components: condenser fan, compressor, 3-way valve - which u can hear if it’s relatively quiet - move through three positions. (I used to hate them)
I work in the central development for a large appliance producer for built in fridge/freezers. At least our valves calibrate by stalling to either extreme aswell. That's done on powerup and every now and then (24h or so), that takes only a few seconds. We don't use any feedback - it's just counting and indexing. If no cooling is detected as expected it will register an error and retry or error out. Ours can only feed either fridge or freezer at a time. These diverter valves are a higher end feature. Some other designs use an air flap to vary air flow between fridge and freezer and only cool the freezer. Other designs only use one cooling circuit and basically rely on over or undercooling either compartment.
The stalling at the range of travel is the same scheme used by GM in their climate controls to actuate the dampers in the dash of the car. But, they use a standard DC motor with an armature that has only three windings, and thus only two wires are needed. The commutator shunts the two terminals together intermittently which act as “pulses” to tell it where it is. They periodically move to an extreme to get a base reference, ultimately stripping the gears in the process after awhile. If you have ever heard the endless clicking from the dash of a car, that’s usually why. One of the actuators has failed. Cheap and clever way to do things, but not very reliable in he long run.
Prusa MK3 and newer do something similar to get the X and Y axis to a known position (driving the stepper motors as the sensorless BLDCs they really are), the mechanicals are well designed so have never heard of it failing.
I have a fridge with this exact valve. It's a three section. The fridge does not cool one of the freezers, and will shut off all cap tubes once one of the sections is at temperature. The compressor will stay on in this event because the freezer has not reached temp, but the computer thinks the valve is open. it's clear from the tear down that something internal has moved to a bad position. Thank you.
Samsung has demonstrated in recent years that they're strictly anti-repair and are devoted to repeat sales through questionable and unethical practices in their designs, marketing, and support.
Just how much torque do you think that tiny stepper motor have? The electronics and the undersized compressor are the fail points. The compressor failure means you have to replace the fridge. As you can't replace just the compressor.
That's not why they go bad. The nylon holds up but when the fresh food EVAP line gets a hole in it the refrigerant and refrigerant oil gets contaminated. I've only seen these going bad due to compressor burnout or excessive moisture in the lines.
I thought most fridges just have a coil in the freezer, and a little door that opens between the freezer and the fridge - if the fridge is too warm, it opens the door and cold air from the freezer circulates into the fridge to cool it. At least that's how old fridges that lasted forever worked. I can see how making it more complicated like this ensures it craps out faster, and people buy more fridges overall
This feature allows the user to independently control the actual temperature of the freezer and fridge. It's certainly arguable whether that is a necessity.
@@kjdude8765 It did with the old system too, just instead of steering refrigerant with a valve to 2 coils, it steered cold air with a door. If the little flapper door breaks, it's really easy to replace. If this breaks, how many people are going to evacuate the refrigerant, cut out the old valve, braze in a new one, vacuum down the system, and put the refrigerant back in? This pretty much guarantees that when this part breaks, the fridge goes to the dump and you buy a new one.
@@gorak9000 Both solutions are in production, and flap+fan is the cheaper one. This is usually used in bigger, more advanced units, where cold air ducting has it's own downsides Also, this valve is pretty reliable and not that expensive to replace. There are much worse things than that :)
Thinking about it some more, one advantage of the more complex arrangement is that it doesn't dehumidify the fridge compartment as much, so fruits and vegetables won't shrivel up as fast.
@@gorak9000 The old system gives you two temperature controls but only the refrigerator is regulated. If the ambient temperature changes or one door is opened more than the other the freezer temperature will change. I suppose the flap could be automated but that adds more complexity. The single evaporator system might also limit system efficiency.
Pretty sure this is what failed on a fridge I was trying to work on a couple months back. Never did end up fixing it because breaking the sealed system was not something I was up to the task of. Customer was able to limp the fridge along by turning the fridge to off and the freezer to it's coldest setting and that somehow prevented both climate controlled areas from freezing over.
I'd be tempted to use a neodymium magnet to manually move the valve to a workable position (and leave it disconnected so it will never move again), then splice a thermostatic control into the fridge fan so once it starts getting cold enough, the fan slows down.
Ive never had one of these valves fail yet. I'd say you have a gas leak. The fridge evap leads on to the freezer evap (opposite to usual) so you have freezer only or fridge and freezer. If you have lost some of your gas turning fridge off would mean only freezer evap being fed and it won't over-cool the fridge trying to get freezer cold. Sealed systems aren't as hard a most techs think, especially with R600A, just have to spend on all the gear.
I've never heard of a fridge where you can set the top and bottom individually before but I buy the cheap stuff when the fridge goes every so often. For something that has alot of computer control capability it's very simple inside, i was expecting it to contain a PCB and its own internal circuitry as things in this day and age tend to do but does make parts cheaper doing it like this. Although the one advantage of not having a central control brain is while the parts were more expensive as they had their own brain, it was technically more cheaper as the main module goes for one thing its a big deal.
The color of that valve disk reminds me very much of the polymer PEEK. If it was made of PEEK, that would also explain the poor scratch resistance. But I'm just guessing here.
It's a good example of why refrigerators don't last for twenty or thirty years like they used to. That valve is going to operate a lot to maintain both sections at their desired temperatures and nylon gears wear out relatively quickly. It's only a small part of a sophisticated system of electronics. If you're an older handyman, you probably remember replacing simple mechanical defrost timers and thermostats to keep a Kelvinator chugging along for decades. Not anymore.
New one on me. Must be the more expensive FF's that have a diverter valve, last one I took apart only had one circuit but more evaporator dedicated to the freezer section. Nice little tear down. I wonder what else this could be used for.../
First time I've seen this too. Most do seem to balance the freezer and fridge sections on a single refrigerant circuit for manufacturing economy at the expense of long term efficiency.
@@bigclivedotcom Fridge freezer the first expansion is into the freezer side, then the cold gas travels through to the fridge side. Temperature control is in the fridge side, because freeze temperature is set by the pressure on suction, so it will always freeze, and then the fridge side simply adjusts how long the compressor runs to cool down the fridge to a desired point. Would say that valve is used to allow the freezer to be set to a higher temperature, and then divert the refrigerant to another expansion device for the fridge side when the fridge still needs cooling, and then both sides get turned off when a defrost cycle is running, but the compressor is kept operating for a minute or three to ensure the evaporators are all empty of refrigerant. Does not need much of a seal, as the pressure is always on the one side, and a slight leak is not a worry in the sealed side anyway.
@@SeanBZA Seems like an easier and cheaper way to get mostly independent temperature control is to have separate evaporator fans with independent speed controls.
Genius. A nylon gear and valve pivot on a pressed bearing plate. Engineered to fail, £1500 American style fridge freezer becomes trash. Recycling nightmare in the making. Much kudos to the guy who repaired his and sent in the broken part.
Interesting, I wonder if these are common now, used to be that simple combination fridges turned the light on if the freezer section needed cooling and the fridge didn't. That was the reason incandescent bulbs where still allowed for this application, effectively as a heating element.
03:38 The stepper motor 'finding a zero point' thing is (AFAIK) what they used to do in floppy disk drives in the 80's and 90's They'd have the floppy disk stepper (or whatever motor it uses) drive something like 40 positions towards where 0 is and you'd hear clicking depending on how close it was to the 0 point (so quite a lot if it was at position 5 or whatever)
@@gcewing iirc the Commodore floppy drives (for the C64) did it as well, which is where I know of it from I've also seen on LGR some small laptops and stuff which make the same thudding noise as they hit end of travel, so it might be fairly common
The spring pushing on the valve does not need to be very strong a in operation the pressure in the housing will be higher than the pressure in the outlet pipes so it will push the valve against it's seat.
Our Samsung with a section that can be a beverage temp, fridge temp, freezer temp or off. I bet this is what it uses. Three total sections in the fridge can be independent controlled. Get some of that AvE magnet showing film. Cool stuff
I'm used to the old style refrigerators, which flow refrigerant to an evaporator in the freezer and use a fan to force cold air into the refrigerator section. I don't like electronics in appliances. It just makes them less reliable and more expensive to repair. My uncle still had a functioning refrigerator from the 50's in his basement, while the refrigerator in his kitchen was lucky to last 7 years before failing. It's like new clothes washers, with direct drive motors. They use less water during rinse cycles, which creates a higher load on the motors and they fail earlier than older, less efficient transmission type washers, that laundromats use. I've had Speed Queen washers from laundromats, that have been running for decades with easy repairs.
Well done Clive, brilliant teardown. These have been around for a good few years now on domestic refrigeration where zoned cooling is required (higher end fridge freezers, wine coolers etc) Another development, originally from Embraco, but no doubt others are doing them too now is the variable speed compressor.
Clive your timing is perfect, fridge section of our fridge/freezer died on Monday with the fridge making some odd ticking noises, you've just explained it!
These aren't common, so check if your model actually has one before you assume its something complex. Most electronic controlled fridge/freezers these days have a single evaporator in the freezer then blow cold air to the fridge, so you probably have a airflow problem; either iced up, or a fan or baffle broken.
I guess this indeed is only a redirecting valve that does not need to have any proportioning abilities. For such appliances I am not even sure if they indeed would use proportioning valves or anything the likes or just work with a fixed orifice at the evaporator. But then, newer more efficient models sometimes have also what they call inverter controlled compressors, which is what actually is a controlled compressor motor, so the compressor does not just switch between on and off, but motor rotations can be controlled to allow less or more flow and thus allowing the compressor to run longer at lower power, which sems to save power and keep a more stable temperature. not sure what that would need.
Now go put the parts on the floor in front of Ralphy's fridge and see if he'll listen to you explain what broke before he just buys a new fridge. ood luck.
Unfortunately these fail constantly and are one of the most common failures on Samsung (and other) dual zone refrigerators. Probably due to the nylon gears stripping out. Before I replaced mine with an Electrolux, this valve failed 4 times in 6 years, and I know many other people who have also had the same failures. You can even search for Samsung freezer or refrigerator compartment not cooling, and this is almost always the culprit. It gets stuck in one position, which will allow coolant to flow only to the evaporator for one compartment.
Great video and a clever mechanism. Thanks for the teardown. You saved me about $1900 for buying a fridge and chainsawing it apart AvE style to see the diverter. 8^) Cheers! PS forgot to mention that the valve piece may be injection moulded crystalline polyphenylene sulfide (PPS - trade names Ryton or Supec) with glass fibre - same stuff the back terminal housings of halogen car lamps are made of. Just an educated guess.
Neat - I haven't seen this application before. Besides the HVAC EEVs (electronic expansion valves) Clive mentioned (might have said "TXV"), this type of stepper motor is also used on some EGR valves (on Toyotas at least). They drive a kind of worm screw instead of the gears in this one.
Hey little bit off topic but I have a faulty E14 lamp bulb that was changing colour temp from warm to cold white, was considering sending it in but idk if it's worth it 🤔 Vid on my page if anyone cares
@bigclivedotcom Yeah, potentially, I do live very close to a train station, and when the trains start moving, I noticed the changes. Then, it progressed to changing every 10 seconds. If you'd like the bulb, I'd be happy to send it over for further exploration.
GM BC from Paul in Orlando. I appreciate your exploration and attention to detail of oddities. Your visual representation of items with a closeup view which is comprehensive in scope. I’ve learned a lot about devices / circuits and enjoy the content. Carry on my friend 😊 your the best!
So what was the failure point? It seems fairly low torque low speed... Bad seal? Or was it a still functioning part This reminds me of the show..."The secret life of machines"
I've always wondered what's inside those. I'm curious how it stays lubricated since it's moving liquid solvent. Also would it malfunction if liquid floods into the rotor cavity.
What a beautiful and ingenuous, albeit fragile, piece of engineering! It won't last many years (unless all the system works as intended - not always the case), but at least it's interesting.
That's from a top end fridge or one that has the freezer on the bottom. Usually all the refrigerant goes to the freezer and by opening or closing a door inside the fridge ( the thermostat ) you allow how much cold air you want to go to the lower part. That keeps it simple, more reliable and cheaper to manufacture. Very interesting tear down.
