Non-Linux Related: Power Supplies

[Ryeker]

Yes, I am fortunate to live in California. I'm no electrical expert and we were having this 'discussion' at work today. Power supplies... does a 300W power supply always use 300W? Or does it mean it can go up to 300W? We were thinking about taking out some 300W PSU's and putting in 230W or 250W to save electricity. I thought that 300W is their maximum limit, so it wouldn't do a thing. Am I wrong? Thanks!

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ryeker@yahoo.com

[ccieToBe]

300W is the maximum. The power supply doesn't, or at least shouldn't be anywhere close to peak capacity except when booting up. A 300W power supply will take up a little more electrical overhead then a 200W one, but the difference isn't much and your equipment and power supply will last longer because of this underutilization.

[crazyox2]

Keep the 300 watter.

[Ryeker]

Thanks for the info. Do you know of any device that can verify this? Something I can use to meter how much power each server is using? Thanks!

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ryeker@yahoo.com

[ccieToBe]

You could use a multimeter, but why bother?

[Ryeker]

We are really trying to consolidate as many things as possible. Trying to save as much electricity as possible.

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ryeker@yahoo.com

[MGP]

You can use an AC current meter to verify power consumption of any AC mains connected electrical device. It's commonly called an AMProbe (although that's a brand name, like Kleenex) and you can get an adapter to use with a regular Digital Multimeter (DMM) or a standalone unit (clamp meter). The clamp meters are handy, since they have a self contained digital display -- so that's what I'd recommend.

They can be very handy for verifying the current draw under various operating conditions. You can calculate the power you are using by measuring the AC line Voltage and multiplying it by the AC line Current (P = V * I). There are other aspects to measuring the power (such as power factor, caused by non-purely resistive loads), but this will get you reasonable close to the actual power usage you have. Some meters have a power calculation function already built into them.

Here are some links to AC Clamp meters:

http://www.contacteast.com/product/prodpage.cfm?grp=A5695EC1-FAA0-11D4-8A710050DA5FEB55&sid=4066B56D-3E9D-4B6D-80F30F7CF67860FA

http://www.contacteast.com/product/prodpage.cfm?grp=4088B8C9-EEE0-11D4-8A710050DA5FEB55&sid=4066B56D-3E9D-4B6D-80F30F7CF67860FA

http://www.davisontheweb.com/shop/page49.html

http://www.davisontheweb.com/shop/page50.html

http://www.davisontheweb.com/shop/page46.html

These are just some samples, almost any of them will do what you want. Since you are looking at (relatively) low powered devices, one with a maximum 10-20 Amp range should be sufficient. A True RMS reading meter will give you more accurate results.

Let me know if you need any more assistance.


[This message has been edited by MGP (edited 20 January 2001).]

[Ryeker]

MGP: Thanks for the info. I didn't know those things were so EXPENSIVE!!! I thought I could buy like a $10 thingie at Radio Shack and plug it in the wall and plug the server to it. LOL!

Ok, I could use a regular multimeter right? Hmm..on second thought, that seems dangerous. I think we'll just forget the idea... http://www.linuxnewbie.org/ubb/smile.gif Hell, if I don't know what a watt is, I should stay away from stuff like this.

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ryeker@yahoo.com

[Shad]

If you really want to conserve power then remember to turn off those monitors. Your average monitor draws 120w to 150w. In sleep mode it is still drawing 12w-30w. (Of course when the monitor is off it still drawing 3w-6w. I don't advise constantly unpluggin the monitor unless you want it to die a premature death)

To give a comparison of power consupmtion (what watts really measure), your typical desk lamp will be in the 60w-120w range. Your average business computer will have an average draw of about 120w-150w. The modern multimedia computer with two cdrom drives will have a draw of about 170w-200w.

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Just a Tuna in the Sea of Life

[Ripley]

Originally posted by Ryeker:
Hell, if I don't know what a watt is, I should stay away from stuff like this.


Yes.

[Ryeker]

We have only one monitor for the other four servers... Thanks for the info guys!

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ryeker@yahoo.com