Bitcoin Data Center 2 MW 277/1 to 240/1 conversion

[caremedical]

Hello there :

I am running a large bitcoin data center and wondering about the best way to achieve 240/1 voltage for computers.

I currently have 500 kva transformer that is 12470 delta primay 480/277 wye secondary. I purchased a new transformer for 2500 kva to accomodate higher power in the data center with the same voltages. But all of my computers PSUs are rated for 240 volts. I considered the following options to get 240 volts to the power supply units cost effectively and wondering if there are better options.

1. Use the taps on 480/277 to decrease by 5 percent and use the 263/1 for computers. It is still a bit higher than the voltage tolerance, but I suspect the PSUs can handle this voltage.

Pros : Less distribution wiring cost
Cons: Probably higher voltage can toast PSUs over a long period.

2. Use a second transformer and get 208/120 and use 208 instead.

Pros: PSUs will not get burned. Transformers easily available
Cons: Almost Double wiring cost. Cost of secondary transformer and loss of efficiency by 1-2 percent due to second transformer.

3. Use secondary transformer and 415/240

Pros: Ideal voltage
Cons: Not easy to find these European transformers and takes long time for getting replacement if one fails.

4. Auto transformers:
I wonder if there are autotransformers for 2500 kva range that can adjust the voltage down from 12470 directly 415/240 at reasonable price. ( around 10K usd)

5. Can I buy a 13500 transformer and connect with my utility which distributes 12470 and then using the lowest tap should probably give around 245/1

Any suggestions ??

 

[ActionDave]

I am closing this thread, in accordance with the Forum Rules.

This site is designed for:

• Contractors
• Electricians
• Engineers
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* This NEC Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.

If you feel this action to be in error, feel free to contact me via PM to explain.

 

[ActionDave]

After hearing from the OP I am reopening this thread.

 

[Ingenieur]

After hearing from the OP I am reopening this thread.

What changed?
seems like no fit for any listed catagory?
threads have been closed that were more inline with the guidelines?


* This NEC Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.

 

[MAC702]

... 480/277 wye secondary. I purchased a new transformer for 2500 kva to accomodate higher power in the data center with the same voltages. But all of my computers PSUs are rated for 240 volts. I considered the following options to get 240 volts to the power supply units cost effectively and wondering if there are better options.

1. Use the taps on 480/277 to decrease by 5 percent and use the 263/1 for computers. It is still a bit higher than the voltage tolerance, but I suspect the PSUs can handle this voltage.

Pros : Less distribution wiring cost
Cons: Probably higher voltage can toast PSUs over a long period....

I'm no computer expert.

Often, voltages can be within 10% of target and be just fine. 263 V is just within 10% of 240 V. But also verify your target is 240 V as many devices these days are labeled for a nominal "230 V" to get 220 - 240 worldwide voltages to fall within that tolerance.

Is there any kind of documentation or technical support with the exact computer power supplies you have that can confirm this will be okay for your application?

And just a thought, though I know very little about the utility side of such transformers, but is it possible that the utility can also bump you down a tap or two and provide your primary with a bit less voltage? But would this screw up anything else on your service?

 

[Fulthrotl]

What changed?
seems like no fit for any listed catagory?
threads have been closed that were more inline with the guidelines?


* This NEC Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.

true, but we had a bitcoin farm question come up a while ago....
so it might be an interesting topic for discussion.
we are talking a half megawatt of blockchain computing here.
that's a lot of oomph.

cannibis grow barns, and bitcoin mines.... welcome to americas
new industrial revoltion.

i'm voting for option #2. some of the other ones seem a bit edgy
in terms of code compliance. i'd like to hear what the engineers
here say.... i'm not hitting the pedal on double the cost.....
Square D 225 kVA 480 to 208Y/120 225T3H Transformer 35549-17212-020 225kVA 208 Y
used is $2,000 online. two of them just about gets you there for $4k.
i don't seen transformers in the other configs getting you there for
less than that.

 

[mike_kilroy]

true, but we had a bitcoin farm question come up a while ago....
so it might be an interesting topic for discussion.
we are talking a half megawatt of blockchain computing here.
that's a lot of oomph.

cannibis grow barns, and bitcoin mines.... welcome to americas
new industrial revoltion.

i'm voting for option #2. some of the other ones seem a bit edgy
in terms of code compliance. i'd like to hear what the engineers
here say.... i'm not hitting the pedal on double the cost.....
Square D 225 kVA 480 to 208Y/120 225T3H Transformer 35549-17212-020 225kVA 208 Y
used is $2,000 online. two of them just about gets you there for $4k.
i don't seen transformers in the other configs getting you there for
less than that.

As interesting as bitcoin mining is, my opinion is giving ANY advice to a computer USER about wiring to 12.5Kv service is CRAZY STUPID! This needs to be closed and deleted!

All the "choices" presented are likewise crazy wrong.

Sent from my SM-G900V using Tapatalk

 

[Fulthrotl]

As interesting as bitcoin mining is, my opinion is giving ANY advice to a computer USER about wiring to 12.5Kv service is CRAZY STUPID! This needs to be closed and deleted!

All the "choices" presented are likewise crazy wrong.

Sent from my SM-G900V using Tapatalk

i don't see the guy as a computer user... more of a facilities manager,
looking at different design plans for his facility.

i don't think he's gonna be down in the substructure with some
3M kits, doing the stress cones himself. so it's hypothetical.
realistically, if he uses three 225 KVA dry type xfmr's, off 480 distribution,
suitably fused, driving appropriate panels, he's got the capacity
without overloading his xfmr's, and it's a code compliant
installation, that he can direct a fine upstanding utah contractor
to implement.

but, i get your point. moderators, OFF WITH HIS HEAD!

:angel:

 

[Smart $]

...
i'm voting for option #2. some of the other ones seem a bit edgy
in terms of code compliance. i'd like to hear what the engineers
here say.... i'm not hitting the pedal on double the cost.....
Square D 225 kVA 480 to 208Y/120 225T3H Transformer 35549-17212-020 225kVA 208 Y
used is $2,000 online. two of them just about gets you there for $4k.
i don't seen transformers in the other configs getting you there for
less than that.

Ummm... (2) or (3) 225kVA'ers are barely going to put him on the map if he is truly looking for a 2.5MVA solution. Or perhaps he meant a 250kVA trannie wired in as a 'buddy' [second] to the 500kVA he currently has.

 

[Sahib]

The OP said the existing supply is 480/277V . He did not say how he managed it to cater to his 240V/1 PSU, as he could adopt the strategy for his 2500KVA transformer also. What prevents him from doing it?

 

[Smart $]

The OP said the existing supply is 480/277V . He did not say how he managed it to cater to his 240V/1 PSU, as he could adopt the strategy for his 2500KVA transformer also. What prevents him from doing it?

Nothing.


Same reason why I'm wondering why he didn't purchase a more compatible secondary configuration, to begin with... and also whether he has taken delivery on said purchase yet. Doesn't sound like it if he's wanting to go out and purchase a 13.5kV one as a replacement...

 

[winnie]

I am approaching this in terms of a discussion with a facilities manager who will be specifying approaches for suitably qualified electricians to implement.

2.5 MVA 12480 to LV is _not_ even in the same county as something appropriate for a DIY installation.

1) It sounds like someone jumped the gun on purchasing hardware. The first thing I would check is if the purchased transformer can be modified for the desired operating voltage.

2) The change from 277V to 240V is a 14% change, so this _might_ be a job for a 'buck-boost' setup. The issue is that this is so large that I don't know how easy it would be to find the necessary components. A bank of 3 240:32V transformers, 125 KVA each, would be sufficient to transform 2500 KVA of 480/277 to 423/244V. I have no comments on the protection requirements for such a large buck/boost setup.

-Jon

 

[zbang]

A couple of things here-

Many people here use language like "I have a XXX" ('I have a 5MW transformer") where they mean "I'm working on a XXX" not "I own a XXX". Reread the original post and it makes more sense that way.


Modern computer supplies are usually rated 100-240V, the manufacturer may allow for some over-voltage but usually not to 277. OTOH, they do not need a grounded conductor, just any two power leads, so running them from two legs of a 240V delta or 208V wye is the same to them as 120V & grounded neutral.

I'd go for #2 (480/277 -> 208/120V), run the computers off 208V, and call it a day. Simple and commonly-available hardware all around, easy to understand for most anyone. Easy to maintain. If you want a higher voltage, look at a 240V delta setup, but the final distribution hardware may cost more and be less available.

Another part is the distribution into the individual servers. Most of them will have a standard C13 or C19* on their supply and give you a cord with either a 5-15, C14, or C20 on the other end. All of those plug into standard computer PDUs. If you go to anything else, you're either getting funny cords or changing out a lot of cord caps and building a lot of receptacle boxes.

*https://www.stayonline.com/reference-iec320.aspx

 

[Fulthrotl]

Ummm... (2) or (3) 225kVA'ers are barely going to put him on the map if he is truly looking for a 2.5MVA solution. Or perhaps he meant a 250kVA trannie wired in as a 'buddy' [second] to the 500kVA he currently has.

i thought he was running 1/2 MW total.... the thread is 2MW. duh.
three 225's would get him there.... but 2.5 MW... if that is his connected
load for real, stacking 225 KVA's at one end of the building isn't the best
idea.

we are gonna need a bigger boat....:slaphead:

 

[Ingenieur]

true, but we had a bitcoin farm question come up a while ago....
so it might be an interesting topic for discussion.
we are talking a half megawatt of blockchain computing here.
that's a lot of oomph.

cannibis grow barns, and bitcoin mines.... welcome to americas
new industrial revoltion.

i'm voting for option #2. some of the other ones seem a bit edgy
in terms of code compliance. i'd like to hear what the engineers
here say.... i'm not hitting the pedal on double the cost.....
Square D 225 kVA 480 to 208Y/120 225T3H Transformer 35549-17212-020 225kVA 208 Y
used is $2,000 online. two of them just about gets you there for $4k.
i don't seen transformers in the other configs getting you there for
less than that.

he needs 2500 kw, 12 225 kva's, not 2

I have an option that may cost nothing or at least be amortized over years
should give him 242 using 1 2.5% tap, 235 using 5%

 

[Ingenieur]

As interesting as bitcoin mining is, my opinion is giving ANY advice to a computer USER about wiring to 12.5Kv service is CRAZY STUPID! This needs to be closed and deleted!

All the "choices" presented are likewise crazy wrong.

Sent from my SM-G900V using Tapatalk

bingo
this requires onsite professional input

 

[Fulthrotl]

I'd go for #2 (480/277 -> 208/120V), run the computers off 208V, and call it a day. Simple and commonly-available hardware all around, easy to understand for most anyone. Easy to maintain. If you want a higher voltage, look at a 240V delta setup, but the final distribution hardware may cost more and be less available.

Another part is the distribution into the individual servers. Most of them will have a standard C13 or C19* on their supply and give you a cord with either a 5-15, C14, or C20 on the other end. All of those plug into standard computer PDUs. If you go to anything else, you're either getting funny cords or changing out a lot of cord caps and building a lot of receptacle boxes.

ok, i was bored, so i did some looking....
the power supplies for this sort of application provide 1,200 watts
at 120V, 1600 watts at 240 volts, so should be around 1,500 watts
at 208. you can't put more than one bitminer on that size power supply.

the connected load is 1200 watts per bitminer. each bitminer for a
15 gigahash processor is almost $4000. with power supply, about $4,200.

on 2.5 MW of available power, pushing from 80% connected load to 90%,
you can run about 1,900 of these bun warmers. the cost of the bun
warmers is right at $8M. just for the boxes and power supplies.

i'm not even going to consider the electric bill for a 24/7/365 operation.

to the OP, you went way over the "bar napkin" design stage where posting
on an internet forum is a feasible option. good luck with your project.
suggest hiring a licensed EE with a background in data centers.

 

[Ingenieur]

Nothing.


Same reason why I'm wondering why he didn't purchase a more compatible secondary configuration, to begin with... and also whether he has taken delivery on said purchase yet. Doesn't sound like it if he's wanting to go out and purchase a 13.5kV one as a replacement...

he bought the wrong 2.5 mva xfmr
could have got a 208/120 or more low taps on a 480/277
or a 13.2 feed by 12.46

 

[winnie]

Using 416/240V is becoming more common for data center applications. The power supplies are designed to work 240V L-N. Why use a 2 pole breaker to supply 208V when a single pole can supply 240V?

-Jon

 

[Ingenieur]

Using 416/240V is becoming more common for data center applications. The power supplies are designed to work 240V L-N. Why use a 2 pole breaker to supply 208V when a single pole can supply 240V?

-Jon

we do not have the whole picture
what we do have looks like a mess due to poor planning and lack of upfront design engineering
he will need some 120
he will need some voltage for cooling

what I would do is get 420/240 out of the existing xfmr
he still needs 120 and cooling power