Measuring (AC) load represented by a PC

Well, I dug up an electronic ToU KWHr meter I designed many years ago and tweaked the gain of the front end -- better suited to "a few amps" instead of a few *hundred* amps. Then, measured the PC with that *and* the current clamp (using the ToU meter as a "sanity check" on the readings from the current clamp).

Numbers were similar -- though *higher* than your above:

100 - 140W (idle, active). I didn't bother with "sleep" or "off" power levels as I am only concerned with the worst case numbers.

If I can find the optical programmer, I bring the ToU meter back and configure it to report peaks -- then see how I can

*create* those peaks.

I was expecting the monitors to be ~20% less and was surprised to see them come in at almost this exact same figure (despite being much smaller -- 19"). So, I'll need to rethink whether I should recommend dual monitors on each workstation or just go with one. I could also point to the extra counter space that they would consume. But, the killer is having to support another KW! Sheesh!

(also makes me wonder what I'm drawing in my office with

6 monitors on! :< )

Measuring will scare you. Since I got the ability to measure, I drastically reduced my power consumption. Decommissioned my entire vampire stereo system, put all the computers on short sleep intervals. I've got three

3W led lamps that light the entire place 24/7. My neighbor calls me "the mole".

I like/need LOTS of light! E.g., 10 "A-base" fixtures in the kitchen alone. Obviously, had to move those to CFL's as "indecents" would have made it unbearably hot! My bathroom has another 8... and I still manage to cut myself shaving! ;<

We burn lots of KW. There are always at least 3 PC's running:

- this machine for email/WWW

- a machine that provides basic services for my private internet

- another machine that I use to FTP/HTTP stuff while this machine is seeing other use (e.g., so SWMBO doesn't complain that the machine is busy) Plus several 100M & 1G switches to enable the network fabric. Surprising how much power they eat!

When working, at a bare minimum, I can fire up a single display on an X-terminal for a total cost of ~120W. Most of the time, I'll fire up a pair of displays, though (so closer to 220W).

If I need a Windows machine, we're closer to 400W for two displays (disk drives, etc.)

If I have to bring a server on line, this can creep up to double that

*without* a display!

Of course, these are in addition to the first three boxes -- and ignore if SWMBO needs to use her laptop. Or her workstation!

[When I'm bringing up a new OS/app in a new bit of hardware, its not uncommon for me to have two workstations running (so that's 4 monitors) plus an X terminal (2 more monitors). Thankfully, some of the devices can be located in other rooms so I'm not pumping extra BTUs into that little space! Though it does get very comfortable on cold winter nights! :> ]

The real kicker is my working hours -- all over the map. So, its usually a PITA to power down (or sleep) a machine as I will probably be using it throughout the "day" -- assuming it isn't busy chewing on some problem (e.g., "make all" or -- *gasp* -- "make world").

OTOH, we do try to economize on peripherals that don't need to be up much. E.g., I have an LJ5p & LJ6p that we use for casual printing. Nowhere near the power hog that the color laser, Phaser or even the LJ4+ are! And, they sleep automatically so I don't have to worry about powering them down if I forget (though they are powered off when not in use).

Likewise, NAS boxen are off unless in use. Ditto for any external drives. Though I need to build a switched outlet strip for all the damn wall warts so I don't have to keep unplugging them when not in use! Why the hell hasn't someone made this, already??

On Sun, 6 Oct 2013 22:30:54 -0400 "tm" wrote in Message id: :

Well, as long as it doesn't draw more than 1A. Full scale AC current is stated as 1.050000, so I believe it's only 6.5 digits. AC voltage is 7.5 digits.

Jeez, pick a few nits, why don't cha.

tm

On Wed, 9 Oct 2013 10:27:56 -0400 "tm" wrote in Message id: :

Sorry. Test and measurement is all about being precise. :)

Until recently, I just let the computers run when I was awake. I have a PDA that constantly monitors and graphs the operation of the gas furnace. You could easily tell from that graph what time I woke up and turned stuff on.

I rarely have anything running when I'm not at the system. I tweaked everything to sleep when not in use. When they're all sleeping, the total baseline consumption for the house is below 100W. And any can be brought back in a few seconds.

>

I "went to be" hours ago (technically, I'm still *in* bed) but have been "up" briefly every hour or two to check on the progress of one of the machines and tickle it on to the next activity (then, back to bed for another "short nap")

This tends to be the pattern here much of the day -- tickle a machine and then move back to continue work on another. Of course, that "move" may just be from one window served by machine A back to other window(s) served by machine B. (You quickly learn to make sure you know which machine has the focus lest you do something you

*really* don't want to do! :> )

I'm impatient. I get annoyed if a screen saver locks the current session and I have to retype a password, etc. Or, if an external disk spins down and I have to wait for it to spin back up before I can examine a directory thereon.

When the ACbrr is regularly pulling a few KW, refrigerator and freezer chest each running on demand, any "conservation" that I might undertake is easily in the noise.

But, its good to see the monitors "sleeping" (reawakened just by moving the mouse) each save me 100W. *That* adds up!

I wonder how many watts burn (here) in idle wall warts, LED indicators (smoke detectors, charge indicators on PDAs, etc.), backlit displays (alarm clock, etc.)? I know it's never dark in the house even with all the lights off, new moon, etc.!

I've A/B compared them with multikilobuck AC test equipment, they're good to a percent or so; more than accurate enough to check VA and W for planning your AC requirements. There are multiple models, and some depth of items measured (you have to push the buttons to get to all the readings).