Bitcoin Data Center 2 MW 277/1 to 240/1 conversion
- Thread starter caremedical
- Start date
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ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Your HVAC load will go up with your mining / IT load. The HVAC load will be likely 480V and make use of the transformer secondary you bought.
The multiple smaller secondary 415/240V transformers will allow you to have reasonable fault currents at your branch circuit breaker panelboards when you serve the IT racks, assumedly via UPSs, unless this is really down and dirty and you are feeding direct from utility.
Transformers are not that difficult to get with 415/240V outputs and when you get multiples, you can get a spare if you like, but transformers don't fail too often.
This is typically the way we serve 240V to data center loads in my practice.
And the winner is! Finally, the right way to do it.
See http://forums.mikeholt.com/showthread.php?t=164464
he already purchased a 2.5 mva 480/277 xfmr
he can easily get 420/240 out of it, possibly at no cost, or small cost amortized over several years
That solution may be acceptable, provided the primary voltage does not exceed 10%. If it exceeds 10%, it may not be possible to bring secondary voltage down to within 10% of 240V for normal operation of PSU of OP as the transformer tapping already used at the rated primary voltage to bring down secondary voltage to within 10% of 240V.
he can have the utility supply a 100 MVA (0.125 x 2.5 mva/(sqrt3 x 13.2 kv) x 13.2 kv/sqrt3) voltage regulator set to -12.5% (11.55 kv output), then use his taps to adjust (could get to 228 vac L-N)
since it is such a large load and he is providing the xfmr they may do it for nothing, or work it into his bill over time
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
I thought the principal reason for using 240Y in American data centers was the energy savings made possible by NOT transforming the voltage a second time.
Yes, it is.
Open Neutral
Senior Member
- Location
- Inside the Beltway
- Occupation
- Engineer
Groan....
Derivation of above (size of utility regulator-100MVA) please.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
That is one reason, but the other main reasons are higher efficiency of server power supply operation and smaller conductors.
Since we only have one native 415/240V UPS that is UL listed, all the others need to step up / down to achieve that 240V voltage anyway, so we might as well stay at the typical 480V and then step down close to the load
caremedical
Member
- Location
- Utah
I am able to stay at my first option without any issue. This is what I did...
1. Installed the transformer with native settings of
12470/7200 Primary > 480/277 Secondary.
2. Changed the taps on the transformer to the lowest level and we got about 250-255 volts L-N setting.
3. I bought few PSUs that are rated for 200-265 volts. Tried them. They worked fine without any issues. Then we used the regular 240 rated PSUs, they worked fine as well. In-fact all of them are performing better as the amperage is lower at a bit higher voltage to get the desired wattage. With lower amperage, less heat and higher efficiency. Have been operating without any issues for the past 2 years.
You can review the benefits of 240 L-N and 277 L-N vs the 208 L-L configuration in this whitepaper.
Only concern I see with my set up is, C13 and C14 outlets are only rated for 250 Volts and not for 277 Volts. after tapping the voltage down, I am close to 250 anyway.
I see various comments about my background. I am a Physician, Oracle programmer and taught physics ( including electricity though mostly DC circuits ) during college days while in medical school to whole bunch engineers.
1. Installed the transformer with native settings of
12470/7200 Primary > 480/277 Secondary.
2. Changed the taps on the transformer to the lowest level and we got about 250-255 volts L-N setting.
3. I bought few PSUs that are rated for 200-265 volts. Tried them. They worked fine without any issues. Then we used the regular 240 rated PSUs, they worked fine as well. In-fact all of them are performing better as the amperage is lower at a bit higher voltage to get the desired wattage. With lower amperage, less heat and higher efficiency. Have been operating without any issues for the past 2 years.
You can review the benefits of 240 L-N and 277 L-N vs the 208 L-L configuration in this whitepaper.
Only concern I see with my set up is, C13 and C14 outlets are only rated for 250 Volts and not for 277 Volts. after tapping the voltage down, I am close to 250 anyway.
I see various comments about my background. I am a Physician, Oracle programmer and taught physics ( including electricity though mostly DC circuits ) during college days while in medical school to whole bunch engineers.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Wow. The original poster resurrecting a 'zombie thread' to tell us what happened.
Regarding your background: this site has specific rules about service professionals in their work capacity. It doesn't matter what you know or if you can actually do what is being described; what matters is that you be functioning in your licensed professional capacity.
For example, if I ask a question about installing an outlet in my kitchen, I would be violating the rules since for _me_ that would be a DIY project. My professional relation to the electrical industry has nothing to do with residential electrical installation.
In your case, if you are working as a facilities manager, and a licensed electrician is doing the electrical work, then your questions are perfectly kosher in helping you plan the work you are having the electrician do. On the other hand, if _you_ are doing this work, then you are violating the forum rules because physician, physicist and programmer all suggest that you are competent and can handle _large_ DIY electrical jobs...but you are not suitably licensed.
Regarding the use of power supplies outside of their rated operating range, this almost certainly violates the electrical code. IMHO as long as you provide the necessary safeguards to ensure that failure of this hardware does not put people at risk, I personally think that this is a reasonable violation...but really that is between you, your investors, the AHJ, and your insurance company. I believe that if you are putting people (employees) at risk while cutting corners then this is morally and legally reprehensible. (What I mean by protecting people, for example: if you cut corners on code to build your server ensemble, but you don't let people enter the server room while it is powered, then the code violations are simply putting property at risk. But if you have employees walking the racks troubleshoot hardware _while it is on_ then code violations put those people at risk.)
Regarding your C13 and C14 outlets, you should get the actual datasheets. It is quite likely that the receptacle configuration is for 250V with a higher actual electrical rating. NEMA configuration plugs and receptacles are often manufactured with a 480V or 600V actual rating, but in configurations specific to 120 or 208 or 250V. In other words the layout of the pins is akin to a color code telling you what voltage that device is intended to supply or receive, but the actual voltage rating is higher.
-Jon
Regarding your background: this site has specific rules about service professionals in their work capacity. It doesn't matter what you know or if you can actually do what is being described; what matters is that you be functioning in your licensed professional capacity.
For example, if I ask a question about installing an outlet in my kitchen, I would be violating the rules since for _me_ that would be a DIY project. My professional relation to the electrical industry has nothing to do with residential electrical installation.
In your case, if you are working as a facilities manager, and a licensed electrician is doing the electrical work, then your questions are perfectly kosher in helping you plan the work you are having the electrician do. On the other hand, if _you_ are doing this work, then you are violating the forum rules because physician, physicist and programmer all suggest that you are competent and can handle _large_ DIY electrical jobs...but you are not suitably licensed.
Regarding the use of power supplies outside of their rated operating range, this almost certainly violates the electrical code. IMHO as long as you provide the necessary safeguards to ensure that failure of this hardware does not put people at risk, I personally think that this is a reasonable violation...but really that is between you, your investors, the AHJ, and your insurance company. I believe that if you are putting people (employees) at risk while cutting corners then this is morally and legally reprehensible. (What I mean by protecting people, for example: if you cut corners on code to build your server ensemble, but you don't let people enter the server room while it is powered, then the code violations are simply putting property at risk. But if you have employees walking the racks troubleshoot hardware _while it is on_ then code violations put those people at risk.)
Regarding your C13 and C14 outlets, you should get the actual datasheets. It is quite likely that the receptacle configuration is for 250V with a higher actual electrical rating. NEMA configuration plugs and receptacles are often manufactured with a 480V or 600V actual rating, but in configurations specific to 120 or 208 or 250V. In other words the layout of the pins is akin to a color code telling you what voltage that device is intended to supply or receive, but the actual voltage rating is higher.
-Jon
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Well cool, thanks for coming back and giving us an update. Just curious, do you take service at primary voltage? Seems like you have lots of control over the transformer, or a really laid back POCO.....
310 BLAZE IT
Senior Member
- Location
- NJ
I am currently working on a project where the service is outside of the voltage limits and the utility can't adjust it. This isn't a code "violation" in my opinion...
Look at the ITIC curves and you'll see that they are suitable to handle steady state voltage deviation.
Also look at ansi C32 to see that utilities may adjust their operating voltage. I highly recommend installing something like a shark power quality meter at the service to alarm through dry contacts if the utility voltage adjusts to the higher region of the C32 curve as this will often occur without warning and will put you outside of this voltage window.
I also reccomend wiring all your circuits with multiwire branch circuiting with upsized neutrals to handle the harmonics if required. It will also make the wiring cleaner and less expensive.
Passive PFC power supplies come with a dip switch to adjust the steady state voltage window for Europe, which just switches in or out a capacitor or inductor. You could open one up and see how easily it is to modify that switched component to be around half it's original value.
If you're using active pfc power supplies you are basicially stuck with the method you're using which may be further enhanced by a ups or line inductor/auto transformer
Sent from my SM-G965U using Tapatalk
Look at the ITIC curves and you'll see that they are suitable to handle steady state voltage deviation.
Also look at ansi C32 to see that utilities may adjust their operating voltage. I highly recommend installing something like a shark power quality meter at the service to alarm through dry contacts if the utility voltage adjusts to the higher region of the C32 curve as this will often occur without warning and will put you outside of this voltage window.
I also reccomend wiring all your circuits with multiwire branch circuiting with upsized neutrals to handle the harmonics if required. It will also make the wiring cleaner and less expensive.
Passive PFC power supplies come with a dip switch to adjust the steady state voltage window for Europe, which just switches in or out a capacitor or inductor. You could open one up and see how easily it is to modify that switched component to be around half it's original value.
If you're using active pfc power supplies you are basicially stuck with the method you're using which may be further enhanced by a ups or line inductor/auto transformer
Sent from my SM-G965U using Tapatalk
Congrats! I love a follow up. A 440Y254 nominal system used to be pretty common back in the day.
Ill check out the white paper.
yuhong
Member
- Location
- Burnaby, BC
I think most vendors can do 277V these days anyway, especially as 3kW power supplies are becoming more common in cryptocurrency mining
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