EATON AMA
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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!
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@scottalanmiller said:
Server Current is the force of the flowing servers in the computational stream.
Don't try to answer electrical questions with IT answers. lol
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@scottalanmiller
-- Mind = Blown -
@dafyre Cha-ching!
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@art_of_shred Actual operating load is the most practical.
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@JColeKen said:
@art_of_shred Actual operating load is the most practical.
How would you measure this in an environment without power monitoring? Or is it basically a guess at that point?
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@JColeKen said:
@art_of_shred Actual operating load is the most practical.
Is there a simple percentage to use there as a ballpark figure?
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@coliver said:
@JColeKen said:
@art_of_shred Actual operating load is the most practical.
How would you measure this in an environment without power monitoring? Or is it basically a guess at that point?
An ammeter works great if you have one and want real numbers.
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@art_of_shred 70-80% is a safe bet. Sometimes it is lower, but that is typically what I default to when sizing.
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@art_of_shred said:
@coliver said:
@JColeKen said:
@art_of_shred Actual operating load is the most practical.
How would you measure this in an environment without power monitoring? Or is it basically a guess at that point?
An ammeter works great if you have one and want real numbers.
Even in the afternoon or do you have to switch to a PMmeter?
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Yes! These can be somewhat inexpensive. We usually see IT equipment running at 60% or less of nameplate rating. The challenge we have when sizing a UPS or PDU, and you will have too, is that generic rules always bite you at some point. If you are the exception, you risk taking down everything.
Keep in mind that sizing a UPS or PDU at less than 80% or 100% utilization is a good thing. UPSs and PDUs are like the breakers feeding your Christmas tree lights - Once you add too much, the lights go off!
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@scottalanmiller Lolz
