This is an interesting and unusual device that was sent by Rob for our exploration and it is a refrigerant diverter valve. An idea is that in a combined fridge freezer, you have a common liquid line. It's got one thick pipe here, which I'm guessing is the feed line and then you've got two lines going presumably the blue one is to the freezer and the other is to the fridge section and depending on which bit needs cooled I Don't know if I can divert it so there's liquid coming out both at once, but it can use this module on top to actually control that to divert where the liquid goes to this one or this one, or perhaps both in differing quantities. Who knows.

Uh, we'll find out when we open it. So Rob speculated this mate of a stepper mortar, but he reckon it was kind of small for a stepper motor. But keep in mind that this is a stepper motor. so this is not small for a step motor.

It has six connections. Provisional probing about does suggest there is a stepper motor. Let's see if we can get this uh off. I'm expecting this to come off and there to be a metal shell underneath because this is how electronic expansion valves work.

An expansion involved just various amount of refrigerant. So here we have. Oh, is the whole thing going to come out? Yes, it is. That's going to make life so much easier.

Let's pull the little caps off. so the bit that uh has just come off here is a step of water. You can see this is the stator. This is the bit that stays still, but the magnetic field rotate inside and it has the six pins.

Probing around shows that the two middle ones are the common and then the outer ones each have four two ohms each and there's two sections of windings in this. It's a very common approach to making these that there's basically two Motors stacked slight out of phase usually and Uh by sequencing the coils, they can actually make the magnetic field rotate around. I'll zoom in this because really it is quite in the distance it can make the magnetic field rotate around these. V Pulls inside and inside.

here will be a rotating magnet. Is this going to be easy to open? I Don't think it's going to be easy to open, but a Dremel will make sure we get into it. Um, but inside here is the rotating magnet most likely a linear actuator based on the magnet rotating Um with a thread and a winding, a little pin backwards and forwards inside which normally it would just be a tiny pin sitting into an orifice to a small hole to vary the amount of Uh liquid that could flow through depending on the position of the motor, but in this case it may be actually just diverting. Um, a sliding valve that diverts between one or the other.

I'm seeing this little pin in the end of guessing that's the end axle inside, but it's strange. it comes through the case. I wonder how they seal that because the rest of it is hermetically sealed. That's the advantage of using the external Uh coil around it.

like that the magnetic field goes through the casing and it can go to the motor inside. Now do I have diver Magnet here? Let's see if I can actually feel the magnet through it. Technically speaking, there is the magnet. Uh, Technically speaking, by moving this round like this, you could theoretically move the Uh core inside.

So to get an initial reference, there's the other end of the shaft down there to get an initial reference. With these, they do want many cheap disco lights do and indeed, what this type of thing does. This is the this is a five volt stepper which are with 22 windings. This one had 40 ohm windings.

so I'm guessing this is possibly 12 12 volt, but with this one, it's geared and it's got a clutch and to get an absolute position when it's powered up, it just assumes it's in the worst possible case position and it counts the number of pulses to wind up from one end to the other, but it doesn't know where it is. it just basically stalls it against the end. In the case of this one, it hits the end and then the clutch rotates. Let's see if I can grab this pair of pliers and rotate the clutch.

So if I'm doing this, you can see it just rotates against the the gearbox. The gears aren't rotating inside, so in the case of this Louver we're just opened to the full extent and stall at the end. But once it's counted that number of pulses that it would have gone from the fully closed to fully open, it knows where it is and then by winding back half a number of pulses, it would wind up to the mid position and uh, it can then control any position within that. It's probably doing the same with this.

So I'm guessing that when this is powered up, you may hear a slight of purring noise from it as the magnetic field slips when it stalls against the end of travel. right? I'm going to have to open this now and the way I'm going to open it I'm going to have to get the Dremel I Think let's get this rubber cap off that is presumably just a anti-vibration mounting and uh, I shall Dremel around the joint here and I'll be back in a moment once I've done that one moment, please, the deed has been done. Let's explore. So I shall Zoom down onto this so we can see it closer.

It says Vietnam 2420 presumably the 24th week of 2020 when I opened it up, it looked like this. Inside it has the motor section and then a very simple rotating valve that is the gas Inlet Port which just basically enters the whole chamber. And if I take this little thing off here, it's got a sliding valve on one side that basically just meets over those two holes down there that you can just barely see. And if you take a look at this bit, it's simply got a rotating shaft in here.

It's not what I thought it was going to be. It's not the sliding one, but it looks as though it's a universal thing that's designed to accommodate multiple Uh applications. but it's got this little metal plate that goes over with. The Main thing here is that it's got this little Tang that sticks down and that presses down on the valve plate and then it's got the actual magnetic rotor, which, uh, the little insert comes out, suggesting this really is universal.

The reason it's a bit black at the end is because I rubbed a Sharpie Roundup For better pictures, here's a magnetic core and a little magnetic magnetic. a little springy plate that pushes the whole assembly down, but that is the rotating core inside. right tail. Let's go down onto the bench.

I shall zoom out. Um, we'll bring in a picture because that's going to be much easier to show you a picture out of focus picture. No, no, it isn't right. Let's zoom up in the picture now and explore the bits pen as a pointy device.

So this is the cup now. It's worth mentioning that the cup uh I thought that was a shaft going through it and braised on and I wondered how they got a good seal around that? It turns out it's just a little dimple little indent in there, so it doesn't actually penetrate at all. However, on this bit, it does have multiple. It's not just get the pipes going in, it's also got the shafts uh, sort of brazed in.

From that side, it makes sense to have everything in the one plate. Uh, so there's the cup. and at the back of the cup goes the little spring that pushes down against the magnetic rotor. And it is worth mentioning that the magnetic rotor can take multiple things in here, so presumably as the other ones are the spiral for winding up and down.

it'll be a universal, uh, sort of core that's used in various products and this, in this instance, it just goes onto a small pinion, a little real that then rides on that wheel to turn it around the Valve wheel and that Valve wheel has a little recess cut out here. I shall just amplify that a little bit under it. rides on. These two ports are leading out to the um, the pipes that are going to the freezer and the fridge section.

and the only other thing worth mentioning on here is that little springy plate that presses down on this so it actually holds it down. It basically sits over there, keeps that out wheel in position and presses it down lightly against that surface. It doesn't have to be a completely gas. Tight Seal Because all that will happen if the if it's it's making it fairly close.

I Think it's a ceramic material? Does it? hold on? I shall rub it with a hard object. It feels plasticky. might just be a slightest ceramic or a plastic. not sure, but it doesn't need to seal completely because if any liquid refrigerant liquid does escape out the other hole, it doesn't really matter because all that will happen is it will go into the appropriate evaporator and have a very, very tiny cooling effect.

Um, take a closer look at that wheel. It has this little uh, well, it's got one at either end. These are the bits that let it index its position and when if I stick that onto that plate now like Ziz and then I bring that bit down here. you'll see that when I wind this round.

Oh, I'll have to zoom down for this. when I wind this round it hits and it won't go any further. So I'm not sure which way it initializes one way shuts off both those ports in the back and the other way has one. I Think it's open? Hold on.

Let me just wind it round that way and that would be covering both ports I think just trying to see here. Hold on. Yeah. I Think it would be covering both ports and if I wind it around the other way.

Uh, it's got one port, this port would be open. Uh, if it's bound round in a particular direction and then when the motor runs and it winds it round, it will transfer to potentially both at once. I Think it will be able to do that so it will be able to divert both at once so it can choose one both or either. uh, just by getting so initially.

when it Powers up, this will spin round until it stalls at on one of the end positions The Chosen position and there it will just skip there. The magnetic field will be just such that it will just shake slightly until it's a stopped initializing and it wouldn't be a huge number of Uh magnetic pulses to make this move. It is a fairly coarse mechanism I mean the the motor itself. It goes in tiny little increments so it does.

You know it will be a fair number, but not as much as the sort of super precise. TXV the thermal expansion valve types of Uh control where it is basically a small pointed and you do going down into an orifice to regulate gas flow precisely. Let me pull out of here. Um, so that's quite interesting.

The motor itself has the set of poles on one side and then in between the two very simple coils here. I should Zoom down this as well. Should I in between the two coils. Here, it has another set of matching poles that are just basically interlocked like that so that as the polarity changes, the magnetic field steps and they are offset from each other so that simply by effect, they change the polarity of each of these coils and it can basically create a rotational movement.

And the change in the polarity is very, very simple. There's a center type winding, so you've got one end, then it winds around in One Direction goes onto a center tap, keeps running around, goes on to the next. Uh Center tap with the look of it, is that right? But by making either of those windings, actually is it going to be that? or is it going to be around the opposite direction? Probably around the opposite direction. but it's got a common connection for the two coils.

But um, by alternating the pin that's connected to either end of that winding effectively change the polarity of this. So by basically changing the plow to that plate, they basically step the motor around and then that it translates to moving the valve. Very, very simple. I Guess that's the secret of mass production though, isn't it? Um, and the drive circuit for this will be very simple.

It'll be something like you can just afford transistors. You could have a Uln 2823 could actually drive two of these. Um, that's just a Darlington driver. All it's doing is, uh, the middle pins are probably connected positive and it's just connecting the other four outer pins.

Uh, onto the negative Realtor actually in sequence to get the rotation. Uh, very simple. A neat little assembly. So I'd like to say thank you to Rob for sending that.

He thought it'd be quite interesting to take apart, and it did turn out to be very interesting to take apart, so thank you for that. Uh, well worth shredding and taking apart for exploration.