Hi, it's tear down Tuesday again this time around I've got something big and beefy. It's a Xantrex 300v 4 amp 1200 W one rack unit power supply. What's a high energy stuff? I Love it! Let's check it out. now.

the unit we've got here is the Xantrex Xfr 300 D4 and it actually comes in a whole bunch of uh, different models from 0 to 6 volts at0 to 200 amps, right up to 0 to 600 volts at 0 to 2 amps. So this one is the second highest they all ,200 Watts but this one's 0 to 300 volts DC output was 0 to 4 amps. Beautiful! And of course these aren't bench power supplies at all. these are designed to go into racks.

this is a one rack unit. uh, high and uh. all the voltage and current knobs are on the front and the power switches on the front and a few other miscellaneous function buttons. but all the um, uh Power output and power input is on the back cuz they're designed to wire into big rack mount Power Systems which could power anything custom.

So even the power cord. even though we got a standard power cord on here, you'll find it's not a standard I input connector cuz these things aren't designed for just uh, general purpose consumer use. And on the back here you can see there's a whole bunch of these uh Phoenix input connectors and you can see that it's really centered around remote uh oper ation. There's various sense lines and remote uh programming so you can program the current and voltage with external resistors or external pots or external.

Or you can do it using digital control or whatever. These are very flexible. Uh Power Supplies Designed for system use and if we pan over here, we'll see that the um, there's the output. There's the output voltage there.

it's it's another uh Phoenix uh terminal block in there with a safety guard on it because these things are high voltage outputs. and uh, there's the Main's input there. It's inside a block, but once again, you've got uh, terminal blocks in there to actually screw that in. There's a big strain relief here, but you can actually uh wire in your cable in your Main's input Cable in directly into the unit.

And here's something you don't see every day made in Canada Beautiful. sorry I don't know the Canadian national anthem if I did I'd sing it. Bring a tear to the eye and my Canadian viewers. And you know we say here on the Eev blog, don't turn it on, Take it apart.

But there's a very good reason why you don't want to switch these things on before you take them apart because lots of high voltage, high energy, uh, storage caps in here. so you really want to let those discharge before you. uh, take apart something like this and any well-designed uh Supply like this. Xantrex 1 Top quality industry reputable brand.

uh I'm sure it's got uh discharged bleed resistors in in there and here we go. Let's lift up the skirt on this thing. and uh, you can expect some big electrolytic, uh caps and quite a few of them. Probably half a dozen or a dozen.

and uh, you can expect some big ass inductors and lots of stuff like that. Plus, uh, some control board. So Tada oh yes, look at that. Let's check it out and it really doesn't disappoint.

Does it? Check it out. We've got one huge mother of a PCB on the whole thing, we've got, it looks like some digital, uh control board over here. You can tell by the packages there. We got our front panel board, but oh, look at this big power supply.

Like I said, a whole bunch of electrolytic caps, high voltage, um, high value caps for uh, storing the DC Because what this basically does is converts your AC straight into uh DC and then um, it's basically a DC uh to DC converter after that. So you got a whole bunch of uh, Emi um, input inductors. Here you got input relays, we got heat sink, and we'll check out these devices later. We got uh, three fans up here.

That's rather interesting placement for the fans. actually. usually you would have them, might have them on the back. uh, panel here or something like that, but there's a big grill on the back.

but uh, yeah, that's rather interesting. They're going through there. There's some cardboard under there we'll check out. In fact, that's a whole cardboard piece actually going square piece going right around there, just sort of separating things a bit and it goes through here like this.

and uh, but yeah, we've got our big Power devices here. couple of uh Transformers and oh, miscellaneous stuff actually I stand corrected. It's not one huge uh PCB If you actually get in, look at the details. There's one large uh input uh filter board here, which uh, basically converts the 240 volts or the mains into uh DC into high voltage DC and uh, then we've got the second board here which looks like your uh, uh, basically your high power DC to DC converter board.

There's another miscellaneous control board here with a whole bunch of sort of analogy type stuff. plus your digital board. And let's start out with our Main's input circuitry here and have a look to see what's happening. Now, what we've got here, here's our terminal block: Input: Two HRC fuses just like you'd see in a multimeter.

High rupture capacity uh, fuses. Then we've got a whole bunch of uh Emi stuff. We got two Ms here. by the looks of it, uh, we've got two relays I'm not sure what the reays are are switching in and out.

Maybe it's um, uh, you know, software controlled. It's like a a a soft start uh Power on or something like something to that effect and uh, couple of big uh, big Power resistor there, a smaller fuse there, not sure what that one's doing and uh, some uh main rated, uh, selfhealing uh caps here and uh, this is pretty much um, just Emi uh filtering so that it just keeps the uh noise um from escaping back out the main. Supply And here's our Bridge rectifier because this is an AC to DC converter so that uh takes the 240 volt or 110volt Mains input and uh converts it uh, directly through a fullwave bridge rectifier as you're familiar with, but this here looks like it might be like an earth terminal or something, but let's take a closer look at that one. and of course a big heat sink here for the bridge rectifier and you can see the white um heat sink compound in there as well.

Now if I take these two uh blade uh terminal wires off here that go through to the main switch on the front panel. You can see the wiring in there coming from this here and it looks like cable, but it's not. It's a dual wire thing going into a little uh, splice um, terminal block there, which, uh, insulation displacement, uh uh, splice terminal. So there's obviously that's some sort of a thermocouple that's measuring the temperature of the bridge rectifier.

So they've put you know they're not just rectifying this and uh, just be done with it. they're actually monitoring the temperature, so presumably they can, um, shut this thing down if it overloads. Yep, you beauty, it's Dave CAD time. Uh, please excuse the crudity of the model.

Didn't have time to build it to scale or to paint it, but this schematic here represents what I think uh is happening on this board and it will map. This schematic will map to the physical components down here as we go along and I'll try and explain that I haven't actually traced it out so it won't be. May not be 100% accurate, but it's pretty obvious what's going on by the physical location of the components. And based on uh, some basic um, uh, theory of how, uh, common mode? um, input Emi chokes and things work.

What we've got is our Mains input over here. We've got our two HRC fuses Here We've got our common mode. Uh, this is a multi- stage common mode uh, choke. So here's the common mode choke with oh sorry, got a filter cap there.

Here's our common mode choke. There's the fer and with the top winding and the bottom winding there, then these two gray caps here and here these go to Earth and then we've got another common mode choke here. once again, the top winding, the bottom winding there going uh in this time a parallel uh filter cap. and then we've got two big Ms here and here because there's two of them I'm fairly certain uh, without having to trace it out that they will go down to earth like that and then you may may not be able to see that in there, but there's a tiny little half watt um axi or resistor in there that's actually one Megan as I mentioned at the start, that's a 1meg bleeder resistor just to, uh, bleed off any voltage stored on these caps.

And then we've got another uh, well, it's not a common mode choke. This time, we've got two separate inductors here and here. and then we've got a another parallel filter cap and then another Mau. In this case, it will be in parallel and go directly across instead of to Main Earth I Almost forgot these two little um inductors.

Uh, two extra inductors here and here. So that's another stage of filtering. and then we'll talk about this. uh, soft start in a second, but then it basically goes into the bridge rectifier which converts the AC input into DC.

So all this stuff we saw is just for Um Emi filtering and, well, it's They've really gone to town on that one and also overload protection with the MS. So so uh, the standard Bridge rectifier here, which is on the big heat sink like this and temperature monitored as we said, converts the 240 volts or 110 volt AC into DC. And these are our main filter caps here. There's actually uh, 10 of them.

Uh, there's a few more off camera here and uh, I looked at them and I saw that they were only Uh 1, Microfarad 200 volt. So I went Well, that's not high enough to put them directly parallel across here, because if you convert Uh 240 volt Mains into DC you're going to have higher than 200 volts. So clearly because they've got them in pairs like this, what they've done is Uh This Is Not Unusual At all, they've put them in series like this to uh, effectively give you a um, a 500 uh, Microfarad. Uh, because it's half the value at 400 volts instead of 1,000 microfarad 200 volts and they've done that five times So effectively.

Um, they've able to create a larger voltage. um, electrolytic filter cap with two lower voltage units. But if you've uh, seen my Uh capacitor tutorial, you know that's not necessarily a good thing because when these things age and get old or they mismatch from the factory, they may not share the voltage. Um, you know you may not get 200 volts across there and 200 volts across the bottom half as well.

So that's why there's two resistors here. there's a big um, looks like a 5 what? it's actually 10K and there's another one here. so that clearly shows that these are current sharing resistors. Um, because that will just help keep this voltage at the center, especially when it first uh Powers up to equally share the voltage across these caps.

And now this soft start circuit as I mentioned, that's what this big resistor over here is doing. I think it's a Uh 15 Ohm 13 wat resistor massive power one. and there's two relays here, so I'm not sure exactly uh, the configuration, but let's just say there's one Rel I'm pretty sure it's just going to short out this 15 Ohm resistor because when you first switch, this thing on these capacitors are going to be discharged and they're going to go. and they're going to suck in all the current.

You're going to have a huge current surge through your diode Bridge into your capacitors. and well, that's not such a good thing. So that's why they put the series resistor in here. surge protection.

When you first turned it on, the relay is unenergized. So you've got the series resistor which limits the inrush current to the capacitor bank, and then after a couple of seconds, uh, determined by this control circuitry or something else down there, then it switches on the relay, shorts it out, and bingo, you can start operation and we get our high voltage DC output directly across the filter caps and Bingo. That's all there is to it. It's uh, pretty basic.

There's nothing unusual or surprising there at all. and um, this. there's a bit of control circuitry down there. It's probably an opamp or comparator or something like that.

And it's uh, obviously, maybe it's doing, um, some extra, you know, uh, Main's failure protection or uh, Mains failure detection or something like that, perhaps, which might automatically. Um, there might be another relay to automatically switch off the power there. But there you go. It's pretty basic operation, but because it's big and high power, that's why you need a huge board this big.

You need the massive inductors, the big filter caps, the big Uh filter capacitors, the big Ms and really takes up a lot of room. And you can actually see this ribbon cable here going from this Main's input board. Um, over here somewhere. so that's obviously.

um, you know to control the mains failure input? uh, detection, or something like that. There may be a bit more. maybe it can measure it or do something like that, perhaps. but uh, clearly they've linked that over here and uh, it does some control and our high voltage DC output here goes over here up into this board.

here. let's take a look at that one. and if we peel back some of this uh, protection cardboard here, we can, uh, see the uh, high voltage. uh, uh, DC from our supply board.

Coming into here, we got another filter cap by the looks of it, and we've got four huge devices mounted on this heat sink which has the three fans. uh, basically. um, it's probably you know, it sucks air from the sides of the unit and uh, I'm not sure which way they're blowing. they're probably blowing out that way and uh, well they would be.

They'd be blowing across these heat sinks here and out the back. and these four devices are high voltage. um High Current um End: Channel Mosfets: They are Irf uh P 460s and you can see we've got some uh temperature sensing coming off here as well in exactly the same uh crimp configuration that we had for our Main's input. and take a look look at this, you'll notice that these screws here.

It's an interesting method to join this board through to this board. They've actually got um, these uh uh, big screw studs here which actually are the high current um uh interface interface connector between these two boards like this. Beautiful and what we've got here is a Uh UC 3875 uh phase shift resonant controller and it controls the four end Channel mosfets up here and if you have a look at the data sheet for that, you can see the output configuration with the four mosfets. and also we've got two IR uh, 20110 highs side uh mosfet drivers.

then we've got our power also going over here via this twisted pair cable into another heat heat sink device with a whole bunch of power mosfets and the switching Transformers and another uh choke in there by the the looks of it and it may be hard to see that, but these Transformers are actually mounted on their own PCB which sits flush with the other PCB You can see the breakout uh tabs there from the PCB panel. And here's the output side of things. We've got two big Uh 400 volt this time. um 330 microfarad uh caps.

looks like there's some um, there's there's position for another couple of caps there. Interestingly, this one uh has a big uh jumper on it. uh, going across the cap like that. So and here's our output terminal over here.

We've got some output uh protection and a little bit of control circuitry around there. but that's probably about it. And what I thought was output protection there perhaps is not. It's not.

These are output filter caps. They're a Z5u dialectric. It says there 1 Kilts at 0.05 Microfarads. Now there's a couple of these devices on the board.

These are very interesting. They they're actually a 105k. that's one. uh, microfarad, of course 400 Vols It looks like they're at Metalized Polyester capacitors.

I Think it's worth digging up the data sheet on these. They've got one of them there. and also, they've got uh, two of them up on the input side of the board over here. and here they are.

They're made by a company called uh, Pactron and they're Metalized polyester uh, pet dialectric. Um, they call them capstick uh capacitors and they basically are ultra high reliability High Mtbf capacitors and made in the US OFA Star Spangled Banner I Love it and uh there for high Ripple current High capacitance uh you know high frequency switch mode uh DC Todc uh converters and they high reliability and it says like all film capacitors, capstick capacitors have true voltage uh ratings and unlike other dialectric systems, require no voltage derating for maximum reli ability. Excellent! This is exciting stuff. There you go.

So uh Uh Oh tells you many. Leading Edge Circuit designs take advantage of a film capacitor's inherent reliability at rated voltage to reduce board size and improveed performance. Well, I Don't think they were going for board size here in this huge one rack unit. uh case.

but there you go. These are little interesting uh beasts here. they obviously a multi pin to get a lower uh inductance. um in there.

So uh, if we scroll down here and take a look at uh some of the specs, they range from 0.33 microfarads up to 20 mic we using 105s which are one microfarad. This gives you the lowdown. uh, miniaturized past filters made possible by high frequency switching technology need tiny but low ESR and low ESL capacitors to attenuate Ripple and reflected RFI over wide uh frequency bands with equivalent series resistance approaching zero Excellent non polar MLP capacitors reliably Syn High Ripple Currents in high density converters run cool and are stable oo what's not to like? but I'm sure these things aren't cheap. You probably pay easily a couple of bucks each for these caps I'm sure maybe even 10 bucks.

Who knows. That's why these things are Mega Expensive these types of power supplies. and we' got some more temperature sensing action down here. Once again, exactly the same, uh, crimped configuration before, and we've got some extra chokes here.

There're only a couple of turns on the Ferites and these look like, um, ceramic, uh, thick film resistors? Silly me. I should have looked at the uh number of legs on these. These aren't mosfets. these are actually dodes.

they're an exus. uh, Dsse 130. uh, can't find any uh info on them, but presumably very high power. and uh, probably quite expensive.

and there's nothing to write home about on the front panel here. Pretty basic, um, seven segment lead display interface with the sockets just putting them out a set distance. Basic, uh, standoff, uh construction with the big 40 pin dip. No surprises.

uh, icl7107 and we have some calibration adjustment pots here. They've been gunked up with the red um set so someone uh has put their tongue at the right angle, tweak those and then uh uh, set those down so vibration doesn't uh, affect them. and uh, standard. LED uh.

standoffs there some basic push button switches and the Uh 10 turn pots for the voltage and current controls. And after all this uh, awesome power stuff I Think the digital side's a bit of a let down, but uh, what the hell? we'll check it out anyway to see what uh processor it's actually using. Nothing exciting I'm sure it's uh, very old school, but we'll check it out nonetheless. And let's see, does it pop off? Oh no, we got to undo the Jack screws for the D9 Now this board here is actually the uh, optional, uh remote control board so you don't get this in the standard configuration.

but Bingo there it is. It might be upside down, but there it is made in Canada interface card. Brilliant. Very old school.

uh dis Ceramics just bent over like this all outed in there. Quite old school. I Love it. Fox Crystal Uh, we got a ROM here and a local regulator and um, a Plcc uh package.

uh processor. You don't see Plcc packages in sockets too much these days. Not too many surprises. It's a motor roler MC 68 Hc1, but of course it seems to be dual processor cuz there's another second 61 uh, 68 HC 11 as well.

Uh, we've got another ROM up here, so there's two ROMs probably an inter interface and control or something like that. We've got a deck up here and uh, not much else. So that's the uh interface board. Couple of miscellaneous 74 HC series circuitry, but uh yeah, not much happening there.

And here's the Phoenix connector inputs. There's some uh jumpers here and uh, once again, uh, a bunch of 10 turn uh trim pots there and one they are set with the red Gunk and there's things like IM monitor uh U monitor I program uh U program and they're uh set. And here's the Uh Phoenix input connectors down here which uh, control the voltage and current remotely. Not exactly sure what this door board here is doing.

It's got a trim podt on it and a couple of Op amps and things like that. so um, yeah, they've put that as a secondary board just uh, basically sitting on top of the other, one directly soldered onto the main board. and basically that's all the uh control stuff inside this. if you ignore the optional Um interface uh board, then this is all your uh remote, uh programming, uh voltage stuff which controls your main DC Todc converter in here.

here's your At. So here's your Uh DC input uh board up the top. It comes in here and it goes across. This is your main um high frequency DC to DC converter section, some output filtering and it goes straight to the output over here and this circuit just controls it with some display stuff and miscellaneous power stuff over there.

Too Easy. So there you go. That's the Xantrex Zfr 300 uh uh, 300 volt uh 4 amp power supply and it's a really topshelf uh brand. Huge quality, industrial, uh designed, properly designed Um system rack mount power supply I Was pretty darn impressed.

It was, um, basically they spared no expense in this thing. It's all all users. Prime Top shelf components. really well designed, really laid out, really modular.

Lot of thoughts gone into these Really: Pros have designed this. It'll be very high reliability and you'll pay for that sort of stuff too. So I hope you like that I certainly did. Was very interesting.

so remember if you like, uh, tear down Tuesday give the video a thumbs up, helps a lot and uh, if you got any um Theory and ideas about uh, how exactly, um all of this uh DC to DC converter Works Jump on over to the Eev blog forum and uh, discuss it cuz this sort of stuff very interesting. Catch you next time.