OT: psu watts & amps ....an volts !

[RJK]

Out of curiosity, I bridged the positive 230 volt mains supply, with my
ammeter, to my PC, at the mains power plug which supplies, amongst a few
other small wattage odds and ends :-
Back-UPS 650, Orange Livebox, Linksys WAG354G, PC system box with Seasonic
SII 430w and several case fans, - Conroe mb and D935 cpu - 3 x hds - dvd rw
and cd rw drives, 2 pci cards, 1 x AGP 6200 card, 19" LCD monitor and Labtec
powerfullish PC speakers.

....and I get a reading of .794 amperes, which calculates out at 182.62 watts
consumption, which in theory means that, (ignoring a few variables for
simplicity), the above should run for 5.47+ hours per kwh ! ...or in other
words here in Somerset, England & EDF Energy - TEN PENCE for almost five and
a half hours !!!

WHERE ...then, is our huge household electricity bill coming from ? (just
kidding - DON'T answer that one please !!! )

I though I had a good grasp on calculating out the required Watts rating for
a PC system box, but, more recently I've been falling back on sites like
Antec's http://www.extreme.outervision.com/powercalc.jsp which makes it a
bit quicker.

....How can I reduce consumption, other than by leaving it all switched off
?

regards, Richard

 

[Colin Barnhorst]

You might also want to ask in the microsoft.public.windowsxp.hardware
newsgroup.

 

[Pegasus \(MVP\)]

See below.

Out of curiosity, I bridged the positive 230 volt mains supply, with my
ammeter, to my PC, at the mains power plug which supplies, amongst a few
other small wattage odds and ends :-

*** No, you did not bridge it - this would have caused a short-circuit.
*** You inserted your ammeter into the circuit between the power
*** outlet and the PSU.

Back-UPS 650, Orange Livebox, Linksys WAG354G, PC system box with Seasonic
SII 430w and several case fans, - Conroe mb and D935 cpu - 3 x hds - dvd
rw and cd rw drives, 2 pci cards, 1 x AGP 6200 card, 19" LCD monitor and
Labtec powerfullish PC speakers.

...and I get a reading of .794 amperes, which calculates out at 182.62
watts consumption,

*** No, it does not. It is 182.6 VA, which is not the same as Watts.
*** The actual power consumption is less but we cannot tell by how much.

which in theory means that, (ignoring a few variables for simplicity),
the above should run for 5.47+ hours per kwh ! ...or in other words here
in Somerset, England & EDF Energy - TEN PENCE for almost five and a half
hours !!!

*** I admire the British for their innovative ways of calculating things.
*** Ten pence for 5.5 hours would be much the same thing as the
*** famous unit of furlongs per fortnight. How about 2 pence per hour?

WHERE ...then, is our huge household electricity bill coming from ? (just
kidding - DON'T answer that one please !!! )

I though I had a good grasp on calculating out the required Watts rating
for a PC system box, but, more recently I've been falling back on sites
like Antec's http://www.extreme.outervision.com/powercalc.jsp which makes
it a bit quicker.

...How can I reduce consumption, other than by leaving it all switched off
?

Use the various power saving modes available on your machine, and
turn it off when it's not in use. And while you're at it: Add up the cost
of the postage stamps you would use for every EMail you've sent, or
the cost of the phone calls if you had rung the receiver.

 

[M.I.5¾]

Out of curiosity, I bridged the positive 230 volt mains supply, with my
ammeter, to my PC, at the mains power plug which supplies, amongst a few
other small wattage odds and ends :-
Back-UPS 650, Orange Livebox, Linksys WAG354G, PC system box with Seasonic
SII 430w and several case fans, - Conroe mb and D935 cpu - 3 x hds - dvd
rw and cd rw drives, 2 pci cards, 1 x AGP 6200 card, 19" LCD monitor and
Labtec powerfullish PC speakers.

...and I get a reading of .794 amperes, which calculates out at 182.62
watts consumption, which in theory means that, (ignoring a few variables
for simplicity), the above should run for 5.47+ hours per kwh ! ...or in
other words here in Somerset, England & EDF Energy - TEN PENCE for almost
five and a half hours !!!

To start with, both your method and calculation are flawed. Power (in
watts) is the Voltage multiplied by the Current *multiplied by the Power
Factor*. You omitted this rather important last bit and probably have no
realistic way of measuring it. This means that the actual power is less
than just the volts times amps (known as VA). Computer power supplies are
switch mode units and take their input at often very low power factors. A
second problem is that your meter is mot likely of a type known as 'mean
sensing, RMS indicating' These indicate correctly *only* when measuring a
sine wave. The current waveform into a Switch Mode supply is never a sine
wave.

WHERE ...then, is our huge household electricity bill coming from ? (just
kidding - DON'T answer that one please !!! )

Everything else?

I though I had a good grasp on calculating out the required Watts rating
for a PC system box, but, more recently I've been falling back on sites
like Antec's http://www.extreme.outervision.com/powercalc.jsp which makes
it a bit quicker.

...How can I reduce consumption, other than by leaving it all switched off

Maplin sell a plug in power meter that will indicate watts far better than
you are managing. If you are that worried, it would pay you to get one. As
a bonus, it measures kWh as well.

http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&&source=14&doy=2m5

It often appears on special offer, so if you are too mean to pay the
advertised price, wait and it may appear cheaper from time to time.

 

[RJK]

LOL .. well done, ...and thanks !
....especially for the Maplin link, I am strongly tempted to buy one.

regards, Richard.