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was wondering who knows what psus will operate on 277 , since i am adding a good amount of 480/277 power

as far as i know right now
dps 850/1000w  110/220-277v
ibm 2880
dell 750
dl580 900/1300w 110/220-277v
HP 1200W Common Slot 277VAC Hot Plug Power Supply Kit (717359-B21)
HP 750W Common Slot 277VAC Hot Plug Power Supply Kit (717364-B21)
HP 500W Common Slot 277VAC Hot Plug Power Supply Kit (717362-B21)


works but is unreliable
dps 2000bb


what else can we add to the list of known to work on 277


known not to work on 277 ( what else can we add to the list that wont work on 277 )

sp10
s2
s4

possibly works on 277

its come to my attention that the sp31 has/may have 2 different models of psus one of which works/ or may work on 277

HPs 200-277V

HP 1200W Common Slot 277VAC Hot Plug Power Supply Kit (717359-B21)
HP 750W Common Slot 277VAC Hot Plug Power Supply Kit (717364-B21)
HP 500W Common Slot 277VAC Hot Plug Power Supply Kit (717362-B21)

here are the quick specs (http://h20195.www2.hp.com/v2/GetPDF.aspx%2Fc04111541.pdf) see page 16 and ff.

EDIT: 480Vac in a WYE configuration and the line to neutral voltage is 277Vac

EDIT-2: Just saw your photo porn pix, so you need a bunch of those psu's... HP 633680-001 500W are 277V and on ebay @25 bucks each -for a platinum psu not bad at all. Specs of the older ones (2013) (http://www8.hp.com/h20195/v2/getpdf.aspx/c04111541.pdf?ver=9)

jstew, please forgive my inexperience with the term 277.
You mention 480/277. Is this three phase power or do you mean you are using a single phase of the three phase and it measures 277? I enjoy learning about anything electrical, and would appreciate understanding a bit more here.

Personally, I use split phase 240, which is simply two 120 which are "off phase" from each other. This is how most homes are wired in the US. I am familiar with three phase 480, but each leg would be carrying a load, unless we get into talking Delta or Wye it should be fairly consistent at 240, and of course we can have a hot leg situation. Maybe that is what you mean? You have a stinger reading 277?

its 3phase 480 one phase to ground is 277 , im actually still learning this myself so i may not give the best explanations

all the psus i have for all the s3's neptunes, sp20s will already run on 277 , im just trying to gather a list so as i ad more hardware i can be on the lookout for other psus that work

right now i am using dry transformers to bring everything to 240 , the machines i have liek the s4's etc with built in psus will stay on the 240 , everything i have that i can move to 277 will be moved over to free up room on the 240

Well, I've read myself into HP's common slot server psu's a bit, because those were the first I bought and you can get them for low on ebay. The wiring for a startup is clean an easy, there are only 2 pins to connect and even a platinum grade with a 94% efficiency is around $20-$30. I'm using 230V with 4x460W and one 1200W psu's. Used psu's above 750W and 94% efficiency are quite rare.

So you can get a lot of 500W 277V psu's with 94% efficiency and a good value/money ratio.
link (http://www.ebay.com/itm/HP-638549-001-633680-101-500W-200V-277V-AC-Common-Slot-Power-Supply-/381347108273?hash=item58ca0f15b1)

There are for sure some 80-90% efficiency psu's with >1000W for less than that.

I know there are two different models of PSU that go into the SP3X. Are both known to not work on 277? It's been a while but I was talking to a friend start of this year doing hosting of SP30 gear and he was shifting some to 277V if they had the right PSU. I could be misremembering and it's entirely possible I'm wrong.

i wasnt aware of the 3x having 2 different models of psu's i just had a friend who had tried to run them on 277 and he told me they wouldnt work , ill edit the first post to state the info u posted

I'm with you now, I just didn't remember it being called 277, or measuring that value, but I understand. It is my terminology mistake I'm sure, but I am with you on what you have.
If I may ask, do you have this ran to your home?

thanks

no this is not being run in my home. i have a small farm at home and a farm in an agricultural location  with a massive amount of power, spring/summer and part of fall we routinely pull 180,000kwh 24/7 , and spikes up over 300,000kwh , i have more power then i will ever use at this location

i dont belive u can get 480v power at most residential locations

I've sold my S4, but I think the boards are internally wired with the normal 6pin PCIe (GPU) plug. So changing the internal psu can also be an option to go for 277V.

yeah one of the s4's i just picked up has the pci-e conectors and a burnt psu , ill be running that unit on an ibm 2880w psu on 277

iirc the early s4's use lugs for getting power to the boards and after a certian batch the went to pci-e connectors , either way though u could wire up a psus for them to run them on 277

Energy from the wall can vary up to 10%, if there's a spike aren't you going to risk your PSUS's going nova?

im having the power company adjust the voltage at the pole on the transformers so its slightly below 277 just incase of spikes , my 240v dry transformersare actually adjusted to output 256v at the outlets and all those have been just fine for the last 9 months

im curious as to what u guys are using for outlets on 277 , ive been using 110/120v plugs for my 240 since they are cheap and i dont have to replace my cords

for the 277 lines i came across a 10 pack of 20 amp 250v outlets for 1$ so i grabbed them to try think ill have any issues with them? they are 6-20p's

not code but they should work.

im aware , but i know that the 110/120 outlets will handle 220/240 just fine , just have to make sure noone plugs in a 110v device into one when its wired for 220 all mine are marked so that doesnt happen

i figured for only 1$ id give the 250v outlets a shot just to get started , eventully im going to do what they guy whos been helping me does and do big lines out to pdus so i dont have to mess with outlets and special cords

friggen 3 phase 480/277 stuff is exspensive

S4 psu WILL run fine on 277.  Not over 300V.  It does require a slight modification.

277V requires half the breaker slots that 240V does.  (If single pole = half double pole)

care to share?

Out of curiousity, is that because 277V is taking 1 leg of 3-phase power as opposed to 2x "halves" of split phase power to make 240V?  And if so, is balancing the 3 legs of 3-phase crucial when dealing with single power sources (like PSU's)?

yeah since ur only pulling form 1 leg u only need a single pole breaker , its not critical to balance the load between all 3 phases on my setup is what the electricall guy told me but my breaker panel rotates which pole leg each single pole breaker hooks into as u install them into the panel.
like this

breaker 1 - leg 1
breaker 2 - leg 2
breaker 3 - leg 3
breaker 4 - leg 1
breaker 5 - leg 2
breaker 6 - leg 3
breaker 7  leg 1
etc etc

we just ran all the main wires today and should be hooking them up to power in a lil while after lunch ill take pictures when its done today , the only think im missing is my plugs and outlets , i may try to wire up a single 110 outlet to the 277 just so i can plug in a single psu and see how it does , if not i have to wait till friday or monday for that stuff to be delivered to wire up all the lines

i might have some 240v stuff laying around that would be safer to use vs the 110 outlet for testing the setup today

Cool.  So when you are powering a PSU or PDU for example, do you have to use a hot, a neutral as well as a ground, instead of the 2x hots + ground that you would see in a typical 240V application of single phase? Or else what do you use on the plug/receptacle where the 2nd hot would typically go?

hot neutral and ground , same way u would wire up a normal 110v outlet

You must make sure your neutral and ground are separated.  install another ground rod at your breaker panel.

Also, you will want to try to balance the load, it will improve your power factor and reduce the amps on your neutral going back to power ground.

If you want to know how to modify the S4 PSU, pm me.  I dont want a debate on here.

bringing this thread back does anyone know for sure if an sp31 will or will not run on 277 depending on the psu

i just picked up some sp31's and i put them on my 240 for now but would like to move them over to 277v power if possible , they have artyserian psu's in the or however the hell u spell it

The PSU from the SP10 is the same or similar to the PSUs in the SP31.

That violates every countries National Electric Codes. For power wiring a neutral must ALWAYS be tied to a ground at the incoming power panel. That is what makes it a Neutral vs just another Hot wire...

Technically, the major distinction between Neutral and Ground wires is that Neutrals are for carrying current whereas Ground is strictly a safety wire.

What you described is commonly referred to as 'isolated power' and is restricted for use only with very sensitive test equipment. A variant of it is an isolated ground setup (usually orange power sockets) that is much like you described except the neutral is still tied to ground but with care that the Neutral/Ground bonding only happens at 1 location.

As to single phase PSU incoming power connections -- Makes no difference if L1 or L2 are Hot and the other is Neutral.

That is correct.  tie your neutral to ground at incoming power location.
A new ground could be helpful at a downstream subpanel.  keep the ground and neutral seperate at subpanel.

just edited the list to move dps-2000bb from working , to working but unreliable
, i have gone threw aot of dps-2000bb in my dc on 277v power i only get about 1-2 months out of them so i dont suggest using them with 277v
i have ibm 2880's that are 2 years old still going strong on 277

....
So -- why -- don't you just pick up a few buck/boost transformers with 32v secondaries and knock the 277v line down to more reasonable 245vac??? They are not expensive. A DPS 2kw supply would need one rated to handle 266VA, call it 300VA with margin.

Do you have any reliability data on the Dell Z750P's on 277v?

i have 4 of those i have been running on 277 for 1.5 years now they are reliable on 277

because its just cheaper to run the reliable 2880's or other 277 reliable psus

 It's not standard, but if you're willing to pay the cost it CAN be done at many or most residences - most of the cost would probably be the installation of a 440v 3-phase transformer, but the wiring would add some too. Standard distribution in a neighborhood from the substation is normally 3-phase at 10kV ballpark.