a cheap power supply?

[Alexontherocks]

update: I have been looking into relay switches but I can't seem to find ones which have a DC output and are rated for 50A...

[Alexontherocks]

Awaiting for the supplies I ask myself: Uncle Jimbo has stated that 12v is a very good compromise when using a TEC. Assuming I rig everything in parallel would it be a foolish idea to emulate a full assembly of typical ATX cables and plugs?

10 psus in parallel for 3.3v +5v +12v and different connections for all he devices. SATA, MOLEX, PCI-E and ATX (+ CPU separate supply). In essence cloning all the typical wiring and having a giant PSU powering my rig.

If this were infact a sound idea, could the 12v line alone handle all the devices (vga/cpu/motherboard/molex/TEC)? In terms of current this is not an intelligent question but would there be any ripercussion to the PSUS or the other devices? Would there any benfit in terms of stability?

In practice it is very easy to accomplish if I can use adequate wiring.

What do you guys think? I am having doubts since it seems a waste not to use a good portion of those 200 amps on the 12v line.

[Uncle Jimbo]

update: I have been looking into relay switches but I can't seem to find ones which have a DC output and are rated for 50A...

Potter & Brumfield has DC relay parts rated 60A per contact up to 28VDC. These have magnetic blow-out to avoid arcing with DC loads and are available with 12VDC coils (or a variety of other voltages). But they are expensive. Since we are not switching any single load over 30A, I have another approach using 30A relays.

Dayton Power Relays are available from a number of sources - I put some links below. Although those are available in 12VDC coil, the 24VAC coil is half the price and also less noisy - the DC version has a little buzz.

Using a 24VAC DPNO with 30A contacts, we can switch all our lines nicely. These are about $17 at grainger http://www.grainger.com/Grainger/items/5Z544


http://www.grainger.com/Grainger/items/5Z546


I have tested contact resistance at 24VDC and below with a 30A load - it is under 10 milliohm. At 30A .01 ohm will drop .3V which should not be significant.

You will also need a 24VAC control transformer - about $12
http://www.grainger.com/Grainger/ite...aseItem=5Z544#



I'll post the wiring diagram in a little bit.

[Alexontherocks]

Don't worry! I am sure you have much more interesting stuff to do than to teach a noob something about switches.

What do you think anyway of the idea of simulating a large atx supply rather than building a separate variable DC power source?

[Alexontherocks]

I am still looking for relays. This one seems good: I am sorry if the info is in italian. I translated some of the most troubling charcateristics (troubling for me that is...)

http://www.webtronic.it/pages/ITA/pr...3&FamigliaID=0



http://www.webtronic.it/schede_prodotti/S66IT.pdf

Descrizione:
Relè Finder 66.82.9.024 24Vdc 2 scambi 30A

• Corrente nominale - 30 A
• Montaggio con alette in testa
• Connessione Faston 250

tipologia: Finder 66.82.9.024.0000 --
Configurazione contatti 2 scambi -- 2 exchanges
Corrente nominale (A) 30 A -- nominal current 30A
Tensione nominale/max. (V) 250 -- nominal tension ???? Does this mean it is unsuitable for switching DC voltages?
Carico nominale in AC1 (VA) 7500
Conatti: Faston 6,3
Materiale contatti AgCdO
Tensione alimentazione 24 V -- supply tension: 24v
Versione bobina DC -- coil version DC
Vita elettrica a pieno carico in AC1 (cicli) 100·103
Temperatura ambiente (°C) -40÷+70
Dimensioni (mm) 51.5x33.5x31
Omologazioni: CE

How should I interpret these specs? I am sorry but I have little experience with relays.

[Uncle Jimbo]

Don't worry! I am sure you have much more interesting stuff to do than to teach a noob something about switches.

What do you think anyway of the idea of simulating a large atx supply rather than building a separate variable DC power source?

First, I am having a good time with this design - you may not know it but you and other posters do a lot of work both in analyzing the designs and testing the ideas. I am thinking of building something a lot like this rig for my own use, and so none of the work is wasted.

With the number of supplies you have in this design, you can easily drive even a large system in addition to your high power loads, but you can do that while still maintaining the big variable design.

Your supplies show 28A at 3.3V, 25A at 5V, and 22A at 12V. Let's say we re-arrange the design to have 6 of those on the base set and 4 on the series set. For the base set, without de-rating, that gives 168A on 3.3V, 150A on 5V, and 126A on 12V.

Comparing with some of the over-the-top big ATX supplies, we can look at how to set up the base set. What becomes obvious is that these monster supplies have relatively standard ratings for 3.3V and 5V, and all the power is on the 12V rails.

ABS Tagan ITZ Series ITZ1300 1300W:
+3.3V@26A,+5V@30A,+12V@92A(6 Rails),
-12V@1A,+5VSB@6A

That's 16A on each of 6 12V rails.

ePOWER EP-2000P10-T3 2000W
+3.3V@28A,+5V@28A,+12V1@20A,+12V2@20A,+12V3@20A,
+12V4@22A,+12V5@22A,+12V6@22A,-12V@0.8A,+5VSB@7. 0A


That's 20A on each of 3 12V rails and 22A on the other 3 12V rails, total 126A

Since there is no significant draw on the 3.3V or 5V rails, your 12V rails should be good for 22A - in other words, this rig would have more power than a $650 'monster' supply. Combining 2 of the base 5V rails and 3.3V rails will give you way more capacity than the monsters on those rails, even with de-rating.

While some of the better supplies provide separate 12V regulation on split rails. You could provide multiple 12V rails like these supplies do. Just don't use any of the 12V rails in the series setup, and provide them as separate lines as ATX 12V rails.

The other reason for split rails is isolation. On this setup, even with bridged rails, you could do that by putting a small series resistance between the main 12V and the 'split rail', and a big cap for each split rail between output and ground. A foot of 18GA should do nicely as a resistor, with .006 ohm, and you should have plenty of that around after you re-work your supplies. Use a 4700 uF 16V cap and you are done. But if you want a premier 200W ATX supply, I think the best way is just use the base 12V rails for that purpose.

That still leaves plenty of power for a 4 PSU series hookup. If you only use the 3.3V and 5V rails from the base set, you can deliver your monster ATX supply, and also series power at 3.3V, 5V, 6.6V, 8.3V, 10V, 12V, 15.3V and 17V, with around 90A available and more on some of the other taps. That should be plenty to run any TEC rig.

Depending on the TEC you use, the power needed will vary. I am currently looking at getting some 24130 units. These are 62mm with a max Qc of 560W at Th 50C, with 32V and 30A. Those are super-efficient at 12V, moving 250W across 20C dT for only 90W in. But to achieve faster cooling, lower temps, or any other desirable goals, you may want to have higher voltage available. At 17V, draw is 18A per unit, but you move 220W across a 30C dT, 280W across 20C dT, and 360W across 10C dT.

With water cooling on the hot side, and using those for a chiller, you would want high power at turn on, and the controller would ramp down as water cooled. Using say 4 of those TECs with a target cold side loop of 5C, and enough capacity on the hot side to keep the hot side water at 35C, when you first turn the system on you would go to full power because the cold side is at ambient. That would deliver over 1400W of cooling, which would drop a 2 gallon cold side loop 3C per second with an adequate exchanger. So after 5 seconds, control power ramps down to maybe 15V. After 30 seconds you are at your 5C control point, and with a 250W heat load your controller will have dropped the voltage to 10V, which is all it would take to maintain temp. That would take total power in of 350W to maintain, so total heat load to the WC is under 600W. At idle, with heat load down to maybe 100W, you could drop to 8.3V and still maintain cols side temp at 5C.

With a monster overclocked dual SLI rig, with everything on the cold side loop, you could see 450W heat load. Still no problem with the setup above - except that the steady state full load would require 12V at 40A to maintain.

That would also have plenty of juice to go sub-zero even with those big heat loads. At the 17V setting, you can get -15C with a 400W load.

And you could do the power switching with a simple thermostat control to set your power relays.

I think that would be a pretty efficient system.

[Uncle Jimbo]

I am still looking for relays. This one seems good: I am sorry if the info is in italian.
...
How should I interpret these specs? I am sorry but I have little experience with relays.

Well my Italian is rusty, but fortunately my strategy lead is fluent, married to an Italian, and also an electrical engineer. She tells me this is a 24VDC coil, DPNO, designed to drop into a Faston 250 relay socket. Good price and would make a nice clean installation if you use the Faston sockets. She also looked up the 24VAC version, same price but the part number is 66.82.8.024 - looks like 8 is AC, 9 is DC in the part number. But she could not find that on the webtronic site.

That relay would work fine for your setup - you would need 24VDC for the relay.

[Alexontherocks]

well...impressive! Since you have an interest to see the project completed I will try to follow you diagram precisely and do any testing necessary once the rig is complete. the 6+4 layout seems efficient and worthwhile given the specs of my psus. Unfortunately I do not have the know how to improvise any part of such a layout so I will trust your suggestions and diagrams.

Just keep in mind I am a student so if you manage to keep the part list (and expense list) to a reasonable total I will be grateful.

P.s. Vi ringrazio entrambi per l'aiuto e la pazienza.

[Uncle Jimbo]

Just keep in mind I am a student so if you manage to keep the part list (and expense list) to a reasonable total I will be grateful.

P.s. Vi ringrazio entrambi per l'aiuto e la pazienza.

nessun problema as we would say in the States... you will save a few euros if you can find a relay that does not need a socket, and you also don't need to have it covered.

[Uncle Jimbo]

Alex - a less expensive relay would be a 30A automotive relay. These are commonly available on eBay at low prices, and at many other suppliers. They are 12VDC coil so easy to switch from your available voltages. You should be able to get them for under €2. Let me know what you find.

[Alexontherocks]

http://cgi.ebay.it/_Ricambi-Auto__RE...d=p3286.c0.m14

something like so?



isn't 20A a little too low?

http://www.webtronic.it/pages/ITA/pr...ds=rel%E8,auto

this seems better but more expensive...

still looking..


P.s. I was thinking of carrying power from the 6 parallel psus to my pc by using 2 wires in parallel rated 4 AWG for each of the 12v / 5v /3.3v lines. The other connections not being used much even under heavy load should only need standard molex wires. I would then connect these lines to screw type connectors united into 3 or 4 rows. From there I will attach standard PCI-E/Molex/Motherboard cables (comprised of multiple wires) on a strictly need to basis. A sort of a ghetto version of a modular design.

[Alexontherocks]

30amp relay is the one you want the other linked is a flasher , so it will power on and off continuously when used

il relè 30amp è quello che volete l'altro collegato siete un lampeggiatore, così esso potere di volontà in funzione e a riposo continuamente una volta utilizzato

thanks....I don't understand why I can't seem to find cheap realys here in Italy. Oh well...the ebay seller ships worldwide and being in EEC I don't have to pay national VAT (IVA in italy) in additio to the price.

Hopefully Uncle Jimbo will not come up with a 50-relay project.

edit: this is even cheaper: will it do? http://cgi.ebay.co.uk/OMRON-RELAY-PW...QQcmdZViewItem

[Uncle Jimbo]

thanks....I don't understand why I can't seem to find cheap realys here in Italy. Oh well...the ebay seller ships worldwide and being in EEC I don't have to pay national VAT (IVA in italy) in additio to the price.

Hopefully Uncle Jimbo will not come up with a 50-relay project.

edit: this is even cheaper: will it do? http://cgi.ebay.co.uk/OMRON-RELAY-PW...QQcmdZViewItem

Yea that will work fine. England is the place for relays - my Lotus has about a hundred of them, maybe more...

Now I guess I need to do the layout

[Alexontherocks]

Just to sum up the ides: The 10 psus will be divided into composite units.

The first will be comprised of 6 psus in parallel and power my system (or any other system) by supplying all lines necessary.

The second unit will be comprised of 4 units in series (and parallel) in order to power up any TEC I wish to use.

Correct?

I leave the layout to you. However do not hesitate to use the correct symbols and component layout. I am quite good at following instructions and building circuits from a predetermined plan. I may not understand it all (at first) but I am almost certainly going to be able to build the system....

P.s. Uncle Jimbo, if you could already suggest how many of these relays are needed (http://cgi.ebay.co.uk/OMRON-RELAY-PW...QQcmdZViewItem) I would be grateful. Mail takes forever to be delivered in this country!

Edit: if you feel that a different design is to be considered more desirable, feel free to do a different layout. You have 10 psus on your hands...enjoy!

[Uncle Jimbo]

Just to sum up the ides: The 10 psus will be divided into composite units.

The first will be comprised of 6 psus in parallel and power my system (or any other system) by supplying all lines necessary.

The second unit will be comprised of 4 units in series (and parallel) in order to power up any TEC I wish to use.

Correct?

I leave the layout to you. However do not hesitate to use the correct symbols and component layout. I am quite good at following instructions and building circuits from a predetermined plan. I may not understand it all (at first) but I am almost certainly going to be able to build the system....

P.s. Uncle Jimbo, if you could already suggest how many of these relays are needed (http://cgi.ebay.co.uk/OMRON-RELAY-PW...QQcmdZViewItem) I would be grateful. Mail takes forever to be delivered in this country!

Edit: if you feel that a different design is to be considered more desirable, feel free to do a different layout. You have 10 psus on your hands...enjoy!

Well I'll give you two options - one which is a little easier to build, uses fewer relays, and gives most of the capability, and a second which is what I think you wanted to do.

Both of them provide a 'super ATX' PSU with 6 20A 12V rails and better than 50A on the 5V and 3.3V rails. Both also provide 80A or more for the TEC supply.

You will need to do a little tinkering but nothing that should give you a problem.

The 'simple' design uses 20 relays, and the full design uses 32 relays.

The simple design:



The full design:



This is a pretty exciting project, I think I may have to build one myself!!

Let me know if you have any questions.

[Alexontherocks]

Well I'll give you two options - one which is a little easier to build, uses fewer relays, and gives most of the capability, and a second which is what I think you wanted to do.

Both of them provide a 'super ATX' PSU with 6 20A 12V rails and better than 50A on the 5V and 3.3V rails. Both also provide 80A or more for the TEC supply.

You will need to do a little tinkering but nothing that should give you a problem.

The 'simple' design uses 20 relays, and the full design uses 32 relays.

This is a pretty exciting project, I think I may have to build one myself!!

Let me know if you have any questions.

*collapses to ground*

Uncle Jimbo I am seriously grateful and so should this community. This may not be as economically efficient as predicted (over 40 euros of relays but it does not matter) but I give it to you: it is the most interesting design I have seen on xtremesystems forum yet.

I am glad I opened this thread.

As for the layout I will let you know. The design seems fairly logical and simple. Much planning out is needed for optimal spacing of components. I will order the 32 relays (If I am to walk this path I ought to aim at the best possibile result ). I will probably grab a large piece of wood and velcro the relays to it so everything is clean.

For now..thanks!

it will probably take some time to see this one finished since I have no other way to get those relays except ordering them from the UK.

[Alexontherocks]

Just one small question: you mentioned using a thermostat type control to switch voltages. From the layout I understand that without some sort of common control mechanism, switching voltages manually would require more than a few seconds. Also is there any way to use the internal 12v supply (from the giant PSU) to power the relays? Could I simply tie in the 12 supply (to the pc) to the control mechanism which in turn would activate the relays?

[Alexontherocks]

I just had to change my avatar pic.....to those who have seen the movie any explanation would be superfluous as to why I had to do it

[littleowl]

I just had to change my avatar pic.....to those who have seen the movie any explanation would be superfluous as to why I had to do it

that is very fitting! I like it! I have only seen half the movie I wish I could have seen the rest!!

[Alexontherocks]

that is very fitting! I like it! I have only seen half the movie I wish I could have seen the rest!!

please do...for your own good, watch the movie. If not for Tony Stark, at least do it for Gwyneth Paltrow.

[littleowl]

please do...for your own good, watch the movie. If not for Tony Stark, at least do it for Gwyneth Paltrow.

yeah I plan on buying it as soon as it hits the stores

[Alexontherocks]

You might want to look carefully in the background of most initial scenes....you might just notice a 10 psus rig powering the ark generator in tony stark's chest. Barely visible but its there.....I believe he used a small cart to pull the thing around.

[Philly_Boy]

You are gonna spend all this money on a high powered TEC set up....10x PSU's in a custom case...to achieve what temps?

I messed with a TEC set up last spring. A 437 watt TEC powered by a proper 24v meanwell PSU with proper guage wires connected from the TEC to the PSU. I put 2x PA120.3 rads, 2x DDC3.2 pumps (with Petra's top) and a D-tek Fuzion on this set up and my h2o temps still averaged 28-30c!!

All this to cool a QX6700 Kentsfield to -10*c idle and +3*c loaded. That allowed me to raise my OC from 3.8ghz (on straight water) to 4ghz. Big whup....

Needless to say I abandoned that set-up and have sold it.

I have a single stage unit on this rig now that I built myself. My CPU has -35c idle temps and -25c loaded temps. The single stage runs 24/7....something I would never trust for the TEC set-up lest it burn my house down....

pic of the ss:

[littleowl]

nice clean setup!!! I like if philly

[Alexontherocks]

I believe you partially missed the point.....The Rig I am building will most probably not cost me more than 160 euros. If everything goes as planned I will have the perfect PSU (capable of powering quad sli easily should I want it) and any TEC around should I want one/need one. Also the project is fun and offers a good opportunity to improve my skills and understanding of both electronics and TECs. There is no waste.

a 1300w Tagan would cost me 500 euros in Italy. Since I don't move my pc I don't need a portable device. 6 psus will surpass the Tagan anyday for a fraction of the cost and the fraction of the maintenance (one of these psus can be replaced with less than 5 euros).

Also I don't intend to overclock the hell out of my cpu but I might want to mess around with TECs one day. The additional cost would be around 20 euros for a module and 5 euros for insulation.

Building a phase unit is not that hard (don't get me wrong it is a nice achievement) and it has been done before. Building a giant PSU? to my knowledge it has never been done on this forum. For 160/180 euros I will have built a PSU worth +600 euros and I will have a dedicated powersupply for a TEC for a total of +800 more or less.

If I sell my current Psu I should be able to get the total net value at 150 euros at most which is not bad!