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Hey all,

Those of you who have been around for a while probably are somewhat familiar with my operation at this point.  For those of you who are not, here are the broad strokes:

I run 25+- miners in 3 different locations, pushing a total of 23,000 MH/s.  All 3 locations are on standard 110v outlets with 20 amp breakers.  This has been great so far, aside from the occasional breaker tripping.  At this point, I am running up against the limits of what I can comfortably and feasibly fit in the space I have access to.  Temperatures are becoming a problem (thought not bad at all), but more importantly I am pretty much maxed out on power draw. 

This has led me to start negotiating a lease on some commercial space (holy shit is is cheap still!), where I plan on moving some miners, and also adding others in a high efficiency set-up.  This is where the bounty comes in!

What I need instruction/help/assistance with:

-Some discussion on 110v vs 220v power.  I have limited knowledge here, and would love a good paragraph or two on advantages, ease of implementation, pitfalls, etc.

-Phase 3 power discussion.  A lot of the listings I looked at had this as a feature....I do not want to research this, and would rather pay a bounty for someone to sum it up with common English. 

-AC cooling.  For those of you working in enclosed spaces....I realize it is almost impossible to cool a sizable farm on AC alone without venting the waste heat.  With venting, how much AC power would one need to properly cool a 15-20 GH/s installation?  Square footage would be around 800. 


I might add more later, and increase the bounty accordingly. 

Also, I realize this info is available all over the forum, but I do not have the time to go crawl through all the topics and sift out the good stuff. 

THANKS!!!

Milk was a bad choice!





sorry, had to get it out of my system

YES!  and it counts! 

220v has less amps flowing through the wires, which should (theoretically) reduce heat, although you'll need to change all the breakers and stuff.

Om nom nom a brand new space, a clean slate. Makes my mouth water. First things first: By all means, wire it up for 240V. All your existing PSUs will continue to work with it with no change in how your rigs work. They will additionally gain from 1 to 3 % efficiency by running on the higher voltage.

The largest expense will be putting in several outlets, but if they weren't there already, it shouldn't cost much more than wiring in 120v. Additionally, you may need to buy either new power cords with different plug ends, or new plugs to attach to the ends of the existing cords.

Remember that when using double the voltage, your amperage is cut in half. So, a rig that was drawing 10 amps will now be drawing 5. The wattage remains the same.

As for cooling: I am not sure of your location, so I don't know the ambient temperatures. How hot does it usually get in the summer, and how cold in the winter? What kind of cooling do you have in your existing locations?

Finally, 3phase power distribution is pretty much out of the picture in terms of wiring it directly to your rigs, although if it is available to the building that will allow you room for much expansion. The most common implementation of 3 phase power is a 480 volts, which you would need to step down to 240 volts with a large transformer (think about the size of a mini-fridge) for a full 200 amp at 240 volt panel.  Your local electrical contractor can tell you what you need and how much it will cost.

Theres not much to say... :

110V vs 220V: If I had choice I would take 220V given that breakers would be the same = 2x power for same amperage breaker (for instance: 110V * 10A = 1100W vs 220V * 10A = 2200W). Also power supplies which run on 220V have better efficiency by a few %.

3 phase: Just means they have 3 phases (somo motors need 3 phases to work properly - because each phase is shifted by 120° so this isnt the same as having 220V with 30A breaker (read down) - but for your purpose it is) and you can use all, so if they have 3 phase 220V with 10A breakers that means you can put a load on each phase of 10A -> (220V * 10A) * 3 = 6600W

About AC cooling better wait for somebody who knows more because I dont know much - i dont use it and it is economically not justifiable to cool only with AC because power cost would likely become significant % of your total power cost of mining farm. Except if power is cheap or free + you have breakers that support your whole farm + AC id rather use extra power on more rigs and use very little or no AC and more venting. Very very rough estimate would be around +-3-7kW depending on outside temperature, and power dissipated from your rigs.

edit: somebody was fast enough to write some before i finished writing an posted this :P

And you can wire 3 phase to your rigs just take each phase seperately and load it with rigs according to breaker spec.. Then take next phase and load it with other rigs etc..

3 phase is likely of no use for you.  The reason for 3 phase is to reduce wiring in datacenters.  Datacenters are "big" so they gots lots of long wiring runs.  So they run 1 3phase circuit to a rack an then split it out as 3x 1 phase 208V circuits.  They can power more gear from a single wiring run.    The issue is the gear to split out 3phase into 3 separate single phase circuits tends to be expensive and you don't really have to make any massive wiring runs for the gear will cost way more than you will save in wiring.  There are other advantages but they aren't really applicable.

Simple version is 3phase or not it will need to be converted to single phase before you plug it into your power supply.

The good news is that is a premises is wired for 3 phase in the US it almost certainly have a subpanel (and likely outlets) wired for 208V single phase (they take one leg of the 3 phase circuit and create a 208V circuit).  In the US if the premises isn't wired for 3phase then it is 120V/240V split phase (same as any residence or office).

So either way you will have power available @ 208V Single Phase and/or 240V "Single" Phase (technically it is split phase but nobody calls it by its correct name).

The main reason for using higher voltage (208V or 240V) is:
a) reduce the # of circuits needed
b) power more devices for the same amperage.
c) reduce power losses in wiring due to heat (power loss is based on current not voltage which is why transmission lines are thousands of volts)
d) improve efficiency of power supplies (ATX power supplies run ~2% to 4% more efficient at 240V)

Using a couple of high amperage 208V/240V outlets you can greatly simplify your wiring.

For example using a PDU like this you can power ~5 KW worth of rigs from a single (NEMA L6-30R) outlet.
http://www.ebay.com/itm/APC-Basic-Rack-Mount-PDU-1U-AP9571-208VAC-30A-IEC-320-12-C13-NEMA-L6-30P-/110850452157?pt=LH_DefaultDomain_0&hash=item19cf33aabd#ht_2994wt_1185

It has 12 outlets so you won't be running out as you will hit 5KW capacity limit first.

http://[img]http://i.ebayimg.com/t/APC-AP9571-Basic-Rack-PDU-30A-rating-208V-12-Port-/00/s/OTAxWDE2MDA=/$(KGrHqZ,!jgE7jIy3h0zBPF2KLBf0Q~~60_58.JPG

30A, derated to 24A (code compliance).
24A @ 240V = 5.76 KW
24A @ 208V =4.992 KW
APC made something like half a quadrillion of these over the years so finding them on ebay is easy. :)

Your entire farm could be powered by 5 outlets and 5 PDUs.  :)

I did a little research before rewiring my garage (did it myself, it isn't that hard if you can handle electrical work) and nothing IMHO beats these AP9571s.  30A circuit is going to power 50% more rigs than a 20A circuit so these PDU are more economical than 20A ones.  You may think well lets just go 50A. :)  I like your style but 50A connectors, plugs, receptables, cables, breakers, wiring, etc tend to be very expensive.  208V/240V @ 30A is the best bang for the buck.

I can't help you on the cooling though.

You are in the lead in my book....I will see what else comes in over the next couple days.

Thanks to everyone who has responded so far!

As for the AC-

I was using a 1500W AC in a small space as I was growing my rigs and it worked great up to about 3.5GH.  So I would say you are talking about 6-8kW in AC.

I am investigating whether water cooling would be cost effective.  I will have access to well water in the space, and could run several heat exchangers.....seems very efficient relative to AC. 

My only concerns are my lack of experience with waterblocks, and the high capital costs. 

Unless you have a very clean well, you might gunk up the heat exchangers. I guess I hadn't ever thought of using anything except for a closed-loop recirculated system.

Did anyone mention that 240 is more efficient ?

I would recirculate standard coolant throught a submersive heat exchanger in a closed circuit. Problem is the water in the well will heat.  Constant fresh water as to be flowing.

This solution might not be cost effective in the short term. It also negatively impact ecosystem.

I would only add that you do not need new cords, you can wire regular plugs for 220.  Just make sure you mark them very well so you dont plug a fan or a light into them.

also, I would use a commercial grade 20 amp outlet when wiring for 220.

Depends on the well.  Some wells will be tapped into a slow moving branch of an acquifier meaning any heat load short of a reactor is going to be insignificant.  Also "earth" is a decent heat sink.  Depending on the depth of the well you have quite a bit of surface area.

Pumping the heated water to the bottom of the well is an option.  Likely need to do some experimenting.  Obviously one could experiment before buying waterblocks.  Heat is heat.  23 GH is likely 10KW?  10KW = 34,000 BTU/hr.

Simply find a heat source (like propane burner) which can heat water dumping 34,000 BTU/hr into the water loop and you got a good test.  No need to even buy a heat exchanger at that point.  The best system would be one that has two wells connecting to same water source (pump cold water out of well, pass through heat source, pump into "hot well").

Sadly I can't put a well on my land because if I could I would be looking into it. 

A flat plate heat exchanger might not work very well (plates are very close together) but a tubular heat exchanger would likely be fine.  They are less efficient (heat transfer vs size) but you can always get a larger one.  If you have very hard water you will get mineral build up on the "well side" of heat exchanger but nothing an annual maintenance and cleaning couldn't handle.

Well, if you want to be code compliant, this probably wouldn't be a good idea.

Most of the cost is labor. Not much difference in outlet, breaker costs when it comes to 20A vs 30A.  Just go 30A from the beginning.  For safety I would go with locking connectors.

NEMA L6-30R outlet and plug.

https://encrypted-tbn0.google.com/images?q=tbn:ANd9GcTYVltPiMYOZ8f5mfUHuvVIhTc3Mww3c9welW8nIULRekMJlkt7

http://www.signalandpower.com/images/original/yp-52.jpg

they dont make 30 amp 110 volt plugs... 

They do but why would you want 110V?

http://www.nooutage.com/images/nema-config-1ph-250v.gif

you dont:  my original post:

I would only add that you do not need new cords, you can wire regular plugs for 220.  Just make sure you mark them very well so you dont plug a fan or a light into them.

also, I would use a commercial grade 20 amp outlet when wiring for 220.

Not a good idea as it is a code violation, you risk voiding your insurance policy, and open yourself up to liability.  Given how cheap the proper outlet compared to the total cost (equipment, lease, cooling) of 24 GH/s farm just use the right outlet.

Which is why I said why 20 when 30 is almost as cheap.  Then at which point you said 30A 110V doesn't exist. It does but not sure what that has to do with 20A vs 30A on 208V/240V.

and how much would 25 special power supply cords? 

I did not even see (not that I looked very hard)   cords with  30amp plug ->  PSU

No such cable exists because there is no PSU which uses that much power.

The cord you are looking for is a C13 to C14.  They cost about $1 to $3 in bulk.
http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10228#1022805

30A outlet -----> 30A PDU (fancy name for powerstrip :) ) -----> 6 to 8 rigs
1 outlet for 12 to 14 GH/s

If you just want to plug 1 rig into each outlet then you don't need 20A.  Plain ole 110V @15A is more than enough to power a single rig. ???

commone D&T  your going round and round....

issue is.  powing our rigs with 220.    I just wire regular 20amp outlets with 220 and use the supplied power cord for the PSU. 

How do you plug in your PSU's to the 220 ?

Exactly. And since I don't have a PDU, this is what I did:

https://i.imgur.com/QCg3dl.jpg (https://i.imgur.com.jpg/QCg3d)

Chopped the end off and put on a 15 amp 240v plug. With a PDU, you can use the link from DeathAndTaxes, above.

I don't think I am, I honestly have no idea what you are talking about anymore or what you are confused by.  Given you seem to be a smart guy I think I am being played so I will stop.


ONE LAST TIME.  

a) that is a code violation

b) why?
110V @ 15 = good for 1 rig.
220V @ 20A = good for multiple rigs.
220V @ 30A = good for 50% MORE rigs at not much more cost.

if you are plugging 1 rig into the wall you don't need 20A OR 220V.

I explained it up thread... twice with both diagrams and pictures and links.  I don't really know how to explain it anymore.  The OP understood on the first try.

BTW, I have a bunch of these left over, if anyone wants them. ;D

https://i.imgur.com/nfteYl.jpg (https://i.imgur.com/nfteY.jpg)

What are your water rates?  If you don't care about dumping it down the drain...

http://img.archiexpo.com/images_ae/photo-g/air-cooled-chiller-for-walk-in-cooler-494146.jpg

I don't know that I would feed one off a well, might run it dry, although I know some people who do and it hasn't been an issue for them (yet).

There were some guys I knew once that were doing some things.  They used these religiously to cool small rooms containing upwards of 10KW/hr of light generating equipment.

Water goes in, water comes out.  The room stays cool, can't explain that!

I've read this whole thread and at ~5 places I saw suggested to use 30A breakers. ... You SHOULD NOT increase the breaker size without increasing the wire size.
It would be more than stupid to use a +20amp breaker on 14 awg wire and feel good about following the 80% load rule.


Sorry but nobody here deserve the full 3 BTC bounty, what the OP asked is a start to finish instructions with accurate safety information.

taken from BLF mini-rig thread thanks to rjk:

Even if water was free,  It cost a shitload to purify water. What a polluter you are. (tap water that is.)

Yes of course - the 30 amp circuit would need 10 AWG wire, but you don't need to run #10 to each rig. It would only go to the PDU(s). From there, you get a pigtail rated for 15 or 20 amps to feed the PSU(s) on each rig.

Well water - I suppose you could pump it up, circulate it thru a heat exchanger, and then dump it back down the well, but that seems like it would be very prone to bad things growing (bacteria, algae, etc) from the heat. Not to mention that it would re-heat the intake water, although I'm not sure to what extent.

Yochdog, I haven't heard from you what kind of ambient temps to expect in your location - lowest winter temp, and highest summer temp. Also, whether you would be allowed to cut holes in the side of the building for large fans. Once I have that info, I could advise better on necessary cooling.

For instance, in Florida you want A/C year round, but in Ohio you would be able to scavenge outside air during the winter using a variable damper.

Planning to cheap out again, my breakers do not have holes to ties them together,

Tell me, is there a part I can buy that ties them together ? ... before I duct tape them ;)

http://www.grainger.com/Grainger/ecatalog/N-1z0dud4

Thanks, 0.5 btc for that. ;)

Unless you have a well and a septic field.  Or maybe you could take that and run with it.  Bury a bunch of pipe and circulate the water through it.  At least I didn't suggest running 30amps of 14/2. 

Are you implying that running water through that swamp cooler is contaminating it?  I'm not sure I get what you're saying.  If you're trying to make a point about the added volume at the processing plant, I don't think your concerns might be a little sensationalist/parabolic.

I dont think anyone suggested running 14.

this is 12/3  run from a subpanel on a 20amp double using regular plugs.  

feeds my seasonics nicely!
http://i1027.photobucket.com/albums/y335/jjiimm_64/10x7970%20rig/IMG_0522jpeg.jpg

Good luck getting the inspector to approve that. ;D

Hi, heres the info. You requeted.  I am a senior level mechanical and electrical engineering student .  I can clarify or simplify any part at your request.

#1


To make what I said brief, the advantages of 3 phase power are mainly geared towards the electrical utility company as cost savings from wire reduction.

#2

Each of the three phases are available to a residential/commercial building.  A schematic is show below.

http://upload.wikimedia.org/wikipedia/commons/4/48/3-phase_flow.gif  

Now what is not pictured in the schematic is the negative wire (since it is not needed).  In our electrical setups we use the earth as a ground (negative wire).

Here are the mathematical results of the power combinations.

Phase 1 - Ground --> 120V (Also called 110V since it dips down as low as 110V, its not perfect)
Phase 1 - Phase 2 -->  240V (Also called 220V since each phases dips down as low as 110V)
Phase 1 - Phase 3 --> 208V

Basically nothing is designed to work on 208V.  It is worthless to your application.  It is a possible combination from the utility power transfer setup.  **One exception.  Some large motors are designed to work on a three phase source.  This makes the motor operate smoother, but since this connection is not readily avialable it is restricted to large commercial machines with specialized connections.

Now here is something interesting for you.

Basically Volts * Amps = Power

Transferring more amps heats up the wire.  This requires a large wire.
Transferring more volts does not affect the wire.

You can think of volts are pressure, and current as flow.  

A larger pressure is nothing.  Think of a compressed air tank.  It just says constantly compressed.
But a flow of air causes friction.  This larger your flow (amp), the more friction shows.  This friction is lost as heat and seen as a loss in efficiency.

This means that the same gauge wire can transfer twice as much power on 220V.  <-- This is what you want.  Its more efficient and has more capacity.

#3

Easiest way to deal with the heat is to vent it to the atmosphere using a fan.  Since you are not living in it so even if its on a 100*F summer day, a 100*F is nothing for computers.  But if you need this environment has to be livable and do not have access to the atmosphere, this means a large air conditioning setup will be needed.  But still a better method would be of transferring heat away (outside).  If you cannot use air (simplet and cheapest).  Then see if you can find an exit using water transfer.  This will allow you the transfer away the heat, which will be stored in the water, before the generared heat has a chance to effect the inside too much greatly reducing the load.  This could mean constantly running water down the drain from a heat exchanger, or better yet.  Running this hot line outside to an evaporator.

If this helped and the bounty is available please send it too.  If you need more help please post or PM me.  I need me some bitlotto money.  Maybe one day, ill win.

13TYbCRVqNcGsnubrU8j1gTDrNUYiuEBhq

That will be news to every datacenter in the world. :)

208V single phase
http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=AP9571A

208V 3 pahse
http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=AP7516

ATX PSU have no problems working @ 208V.

The rest of the info was good just not sure what you were trying to say with the quoted sentence.