Re: "Mysterious" system crashes
- From: sms@xxxxxxxxxxxx (Steven M. Schweda)
- Date: Fri, 16 Nov 2007 19:38:59 -0600 (CST)
From: Doug Phillips <dphill46@xxxxxxxxxxxx>
On Nov 16, 6:20 pm, s...@xxxxxxxxxxxx (Steven M. Schweda) wrote:
From: Doug Phillips <dphil...@xxxxxxxxxxxx>
[...] When VA and
Watts are both shown on an appliance tag, and they're different
numbers, VA is used to indicate peak, and Watts is used to indicate
the average draw; the amount of power consumption you're most likely
to see on your electric meter if the thing runs all of the time.
This is simply not true.
Maybe you came in late.
Oh, I wish. How I wish.
I'm talking about the power consumption of the
appliance (the computer), not the power rating of the UPS.
Same here.
The rating
tag on a UPS or even a power stip is *not* the same and it's *not*
what I'm talking about, although it should give both and in and out
ratings. You need to know or guesstimate the power consumption of the
"appliance" to determine the rated-size of UPS you need to buy.
Yes, power strips don't consume power (give or take an indicator
light, or a bit of circuitry in a fancy one). I'm pretty sure that I
never said anything like that.
Wondering if I've just dreamed this, I checked various *appliance*
rating tags (without pulling things out or crawling behind something)
and only found one (on a TV) where VA and Watts are both listed:
120 VAC 60 HZ 450VA 240WATTS
I never said that appliances couldn't have different watt (real
power) and VA (reactive power) ratings.
Now, how do *you* interpret that?
Not knowing what the thing is, I'd say that it probably has a motor
or other inductive load device inside (as capacitive loads are
relatively unusual). I'd also say that if I were trying to estimate its
cost to run, I'd use the 240 watt figure, because that's how my bill is
calculated (that is, based on real power). On the other hand, if I were
deciding how fat the wire leading to the thing needed to be, I'd use the
450 VA figure (over 120 volts), because that's what'll determine the
current in the wire (that is, 3.75 amps, not 2.0 amps). There's nothing
here related to peak anything versus average anything.
If you don't understand how 120 volts, 3.75 amps, 240 watts, and 450
volt-amps can coexist (yes, steady-state), and apparently you don't,
then you need a better education in AC circuit analysis. (This is
merely ignorance, not evidence of a character flaw, but if you keep
insisting that you really _do_ understand this stuff, then you'll be
skating on thin ice in that regard, too.)
(Quite a few of the ones I looked at just show Volts and Amps and
expect us to know how to multiply.)
Or they offer only resistive (or small) loads, and there is no
difference (or it's so small that no one cares about it). They may also
expect you to know when you're allowed to do the simple multiplication
and when you're not.
On to better things.
Good plan.
Executing plan....now....now....now
Success seems to elude you, but please keep trying.
------------------------------------------------------------------------
Steven M. Schweda sms@antinode-org
382 South Warwick Street (+1) 651-699-9818
Saint Paul MN 55105-2547
.
- Prev by Date: Re: "Mysterious" system crashes
- Next by Date: Re: system constants in COBOL
- Previous by thread: Re: "Mysterious" system crashes
- Next by thread: Re: "Mysterious" system crashes
- Index(es):
Relevant Pages
|
