EATON AMA
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Explain it like I am 5. How do you correctly calculate the power usage of a 3-phase PDU? I have been wrestling with this and would really love a simple calculator or spreadsheet or something.
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@art_of_shred I think everyone just left the techy questions to @JColeKen to fend for himself
Don't eat him alive! -
I recently started a discussion here on ML about why UPS companies like to always recommend "server-grade" UPS for servers, even though they might not really need it.
What is your feeling on this, and is there any times you think a desktop level UPS might be OK for some server applications? (As the included thread seems to lean in that direction.)
http://mangolassi.it/topic/6865/server-ups-recommendations/2
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@coliver said:
@JColeKen said:
@JaredBusch Around $3,500-$4,000, not including the automatic transfer switch.
Oh... man that is inexpensive... might need to look at that in the near future. I've learned so much from this AMA.
Yeah, the wheels are turning in my head, now. Hmm....
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@Nic One of the things Eaton is most excited about is CI and hyper CI...we've made a lot of headway with others in the industry to try to make lives of IT pros easier and make their solutions more reliable. http://powerquality.eaton.com/About-Us/Alliances/default.asp
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@molly said:
@art_of_shred I think everyone just left the techy questions to @JColeKen to fend for himself
Don't eat him alive!You can feel free to answer my line conditioner question...
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@art_of_shred If I felt I adequately could, I would!
I have come to terms that I'm no IT pro. -
@BRRABill We tested that theory on a different forum with a user base. We provided an “off-line” UPS in their typical environments. Communications is really what makes a UPS “server grade”. So if being able to remotely shutdown (or with integration of a hypervisor) migrate VM’s to a safe host (a server that is not on battery), which is usually the case, we would recommend sticking with something that talks to you and lets you take actions or have those actions preemptively ready to go.
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@molly It's really an electrician's question. I'm just curious if anyone has an informed answer for it.
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@BRRABill There are a few things that go into it. One is the level of protection...that is typically the most important. Others included extended battery capability and network capability (many more, just naming a few). In some cases you may only require a certain level of protection and limited communication/extended run capability, so in those cases you'd be fine running a lower end UPS (less feature rich). But in general,we try to make it easy for someone off the street that knows nothing about UPS to be able to purchase protection for their "servers" and make sure that offering will provide them everything they would be required.
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@gbeyhaut said:
@JaredBusch prices on the web!! NEVER! www.cdw.com should have some prices. To be honest we sell these primarily through electrical distributors like Wesco and Rexel.
Even so, I think Jared is correct and getting MSRP prices or some guidance on pricing without needing to go to random online resellers. This presents a huge barrier to research and puts off IT departments. It works for IT that is being driven by their resellers, but not IT doing their own IT work.
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@scottalanmiller completely agree!
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Two easy ways, one hard way.
Easy
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Add all your IT load wattages together. Done
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For 120V loads, add all your currents per each "segment" and multiply them all by 120V. If you have three phases, the process is the same: take all the currents, add together, multiply by 120V. Done!
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For 208V loads, avoid the physics lessons. Take the current on each "segment" and multiply by 208V * SQRT(3). Done!
For those math nerds out there SQRT of three is based off of 120deg phase angle from your unit circle. OK. There are great resources out there on three phase power, but don't make it too complicated. The above equations can get you there.
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@JColeKen Yea, I kinda figured that. My family is chock full of Electricians... all I need is somebody to wire it up to my house's gas line and I'm golden, lol.
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@JColeKen said:
@BRRABill There are a few things that go into it. One is the level of protection...that is typically the most important. Others included extended battery capability and network capability (many more, just naming a few). In some cases you may only require a certain level of protection and limited communication/extended run capability, so in those cases you'd be fine running a lower end UPS (less feature rich). But in general,we try to make it easy for someone off the street that knows nothing about UPS to be able to purchase protection for their "servers" and make sure that offering will provide them everything they would be required.
Could you give some details, say, in the difference between the 5S1500 and the 5P1500 that might sway a person either way?
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@windso said:
Two easy ways, one hard way.
Easy
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Add all your IT load wattages together. Done
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For 120V loads, take your server currents and multiply them all by 120V. If you have three phases, the process is the same: take all the currents, add together, multiply by 120V. Done!
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For 208V loads, avoid the physics lessons. Take the current on each "segment" and multiply by 208V * SQRT(3). Done!
For those math nerds out there SQRT of three is based off of 120deg phase angle from your unit circle. OK. There are great resources out there on three phase power, but don't make it too complicated. The above equations can get you there.
Wow... that is the simplest I've come across, we are running 208v. Thanks.
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@windso said:
- Add all your IT load wattages together. Done
Wattage of the Power Supplies, right?
- For 120V loads, take your server currents and multiply them all by 120V. If you have three phases, the process is the same: take all the currents, add together, multiply by 120V. Done!
What do you mean by server currents?
- Add all your IT load wattages together. Done
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@dafyre said:
@windso said:
- Add all your IT load wattages together. Done
Wattage of the Power Supplies, right?
- For 120V loads, take your server currents and multiply them all by 120V. If you have three phases, the process is the same: take all the currents, add together, multiply by 120V. Done!
What do you mean by server currents?
Current is amps. My question about the wattage is do you go by the labeled wattage of the power supply, or do you need to calculate the actual operating load?
- Add all your IT load wattages together. Done
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Server Current is the force of the flowing servers in the computational stream.
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@dafyre , good point, I edit the wording. See above. Really I mean current on each phase. Poorly worded. Sorry!
