In article , Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

I was expecting to see stuff about power consumption by "wall warts".

Those have been called "vampires" by being 2-pronged/"fanged" constant
consumers of small amounts of electrical energy that can become somewhat
significant in terms of electrical energy consumption if one has several
being powered 24/7, though this is well behind a refrigerator and behind
most climte control and lighting electricity demand.

I do believe that there should be some "energy efficiency" requirements
of those.
I find many "switchmode" cell phone chargers to do well in that area, as
I estimate from their heat output when loaded (mostly somewhat less than
that of wallwarts" with iron core physical transformers) and when
unloaded or largely-unloaded (they become outright cool to the touch when
being connected to a cellphone that has detected that its battery got
fully charged).

I also see many "wallwarts" with more-traditional iron core transformers
easily consuming a watt or two less apiece if they get made with heavier
gauge wire, more turns of wire per unit area of
wound-around-core-cross-section, and/or thinner core material laminations
preferably of some decent material - preferably "29M6" or only one or two
minor steps cheaper than that. Maybe requiring next larger size (usually
step up in most-traditional inch measurements for an "E-I" transformer
core has longest dimension upped 5/16 inch, another upped 1/4 inch
and the third upped 1/8 inch, and there are often some options to more
mildly increase only the "stack thickness" of a laminated core by 1/8 inch
that will even alone fairly often do well).

- Don Klipstein )

In message , Don Klipstein
writes
In article , Michael A. Terrell wrote:



I was expecting to see stuff about power consumption by "wall warts".

Those have been called "vampires" by being 2-pronged/"fanged" constant
consumers of small amounts of electrical energy



That may explain why they haven't become known as 'vampires' in the UK.
Everything which plugs into a wall socket has to have THREE pins. The
live and neutral receptacles have safety shutters, which are moved aside
as the ground pin (which is somewhat longer) enters. Even in the UK, no
self-respecting vampire would use three teeth.
Ian.
--

Thanks a lot. I get part of it, but it hasn't sunk in to the level of
real understanding yet. I"ll read it a couple more times.

Sending an email of this to myself as well as you.

On Fri, 15 Jun 2007 22:16:33 +0000 (UTC), (Dave
Martindale) wrote:

mm writes:

I'd like to better understand that and what Dave said. I once asked
about the difference between volt-amps and watts and didn't get a real
answer iirc. I haven't googled.

To calculate watts, you take instantaneous measurements of voltage and
current and multiply them together, then integrate (average) the result
over some time period. You can do this in analog circuitry using an
analog multiplier device, or you can do it digitally by making many
measurements of voltage and current per cycle and multiplying them
digitally before filtering. Either way, you need a special meter that
measures and multiplies two quantities instant by instant.

To calculate volt-amps, you measure and integrate voltage and current
separately, then multiply the two numbers together. This can be done
with two independent ordinary multimeters.

If the load is resistive (e.g. an oven, baseboard heater, etc) there is
no difference between watts and VA. The current is always in phase with
the voltage, the product of the two is always positive, and the two
different calculation methods give the same answer.

But that's not true of capacitive and inductive loads. In capacitive
loads, the current waveform is up to 90 degrees in phase ahead of the
voltage waveform (i.e. peak current happens as voltage passes through
zero, where its rate of change is greatest). If the phase shift is
exactly 90 degrees (pure capacitance), then for half of the cycle the
sign of the current and voltage are actually different, and the product
of the two is negative for that portion of the cycle. The same is true
for inductive loads (e.g. transformer with no load on it, unloaded
motor) except the current waveform lags the voltage one by up to 90
degrees.

Whenever there is a phase shift between current and voltage, the VA
remains the same, but the watts measured are reduced. Effectively, for
one portion of the AC cycle the circuit accepts power from the utility,
and for another portion of the cycle it feeds some of that power back to
the utility. If the phase shift is a full 90 degrees (either ahead or
behind), the net power is zero!

Both measures are important. Watts is the amount of actual power
consumed by your device and converted into heat, light, or mechanical
motion. Voltage determines the amount of insulation needed on wires and
the number of turns of wire in a transformer, while amps determine the
size of wire needed to carry the current and the resistive losses in
that wire resulting from current flow.

So VA is generally the right measure to use when sizing transformers and
wiring, not watts.

Dave

Don Klipstein wrote:

In article , Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein )


Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In article , Michael A. Terrell wrote:
Don Klipstein wrote:

In article , Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein )

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

- Don Klipstein )

In article 6zeci.5552$O15.1004@trnddc03, M Q wrote:
Power Vampires are a significant problem. While each one
is (usually) not significant, altogether they can add up
to quite a bit. I have found that they can add up to
several hundred watts. "Kill-a-watt" can be quite useful
if you can guess where they all are and they are plug-in
devices. As you can see, not all plug in the wall. Here are some
idle power consumptions that I have measured:

Doorbell transformer 8 watts
cordless phones 4-9 watts
DirecTV receiver (off) 34 watts
TV (off) 17
Garage door opener 2.5
Fax machine 10
Gas furnace 20
Newer gas furnace 27
Central AC outdoor unit 20-40 watts (two different units)

Are these watts or volt-amps? Most of these sound high to me.

- Don Klipstein )

Don Klipstein wrote:

In article 6zeci.5552$O15.1004@trnddc03, M Q wrote:
....
Doorbell transformer 8 watts
cordless phones 4-9 watts
DirecTV receiver (off) 34 watts
TV (off) 17
Garage door opener 2.5
Fax machine 10
Gas furnace 20
Newer gas furnace 27
Central AC outdoor unit 20-40 watts (two different units)


Are these watts or volt-amps? Most of these sound high to me.

- Don Klipstein )

You should probably take those numbers with a grain of salt.
I really need to remeasure, now that I have a Kill-a-Watt
to easily give me real power. (at least for plug-in devices).
The wired in devices are definitely VA, as I used one of those
clamp around current probes rather than breaking the circuit.
(although the 40 watt AC outdoor unit was a resistive heater).
The plug in devices may be VA or Watts.

I will repost here once I have remeasured with real power numbers.
(don't hold your breath -- it may be a while).
I would encourage people to make their own measurements, as devices
vary greatly. I have noticed that newer devices are often much better,
as measured by the "how warm does it get?" method.

On Sun, 17 Jun 2007 14:46:43 +0000 (UTC), (Don
Klipstein) wrote:

In article , Michael A. Terrell wrote:
Don Klipstein wrote:

In article , Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein )

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

Part of the thread is in alt.home.repair AND sci.electonicts.repair.

Another part is only in ahr.

I think I brought in ser, and the answers about wall warts are in the
other part of the thread.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

You read ser iirc. So it's not that your server is screwy or that you
failed to notice.

There is almost always a third possibility, even though often people
(I'm not referring to you) don't want to believe it (Either it's
amnesty or it's deportation)

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

OH, I should have read this sentence first. OOPs. To find the posts
in ahr, you should come with the subject name and the date, because
there is so much traffic on Ahr that it will be hard to find
otehrwise. Or use groups.google and the exact subject name.

- Don Klipstein )

On Fri, 15 Jun 2007 15:09:42 -0500, "dnoyeB" wrote:

On Wed, 13 Jun 2007 14:51:20 -0400, Zephyr wrote:

Hey folks,

I'm curious about power consumption of things like the power supply for
my dell laptop
its and AC/DC adaptor, and when the unit is charging my laptop it gets
quite warm.
from that I infer that its using a fair amount of power.


traditionally, transformers do use power even when their device is not on.
There is loss in the field. But more modern electronic ones do not
require anywhere near as much. Recent cell phones I think are electronic
transformers. Those I tend to just leave plugged in, LED and all!!

It's probably hard to tell the modern ones from the older ones. They
all have cases made of plastic, which is the only clue I usually get
for "new".

I've taken apart some of the almost cube=shaped plastic ones and all
they have inside is a metal core transformer and, rarely and for big
ones, a fuse wire. The big ones get less hot because they spread the
heat over more area.

Is 2 to 2.5 cents per 24 hour day not worth worrying about? 2.5 cents
is 9 dollars a year, times however many of these one has. Maybe 10? =
90 dollars a year, plus 90 dollars of wasted electricity and fuel at
the electric generating plant, plus half of year as heat that people
use AC to remove, another 90 or 180 dollars.

Not that I unplug everything. It's easy enough to do so where the
receptacles are handy, but where they are behind the bed, or behind
the bookshelves, not so easy.

In art. , mm wrote in part:

Is 2 to 2.5 cents per 24 hour day not worth worrying about? 2.5 cents
is 9 dollars a year, times however many of these one has. Maybe 10? =
90 dollars a year, plus 90 dollars of wasted electricity and fuel at
the electric generating plant, plus half of year as heat that people
use AC to remove, another 90 or 180 dollars.

I think that air conditioning bit is exaggerated.

If you convert 90 dollars worth of electricity to heat, and half the
year you have to pump out the heat, that is 45 dollers worth of heat to
pump out per year.

Divide by the COP - which is (ideally) the EER divided by 3.41 (number
of BTUs in a watt-hour). COP may be somewhere around 3 or 4 in practice;
I would have to check that out better.

If COP is 3, then walwarts consuming $90 worth of electricity annually
in a home where it is air conditioning season half the year will add $15
to the electric bill.

Meanwhile, that 2.5 cents per day sounds a bit high. It appears to me
that a worse older type wallwart has idling losses around a watt or two,
based on heat output.

This is about .7 to 1.5 KWH per month. Even at Philadelphia residential
rate surcharged for use beyond some threshold during air conditioning
season, maybe 18 cents per KWH (IIRC), that is at most 27 cents per month
during air conditioning season. Without the surcharge, the per-KWH rate
including transmission fees and taxes is about 14 cents, for a maximum
around 21 cents per month.

However, I do think this adds up, especially when you have a lot of
them.

================================================== ==================

Consider energy efficiency next time you are shopping for a fridge.
That can make a difference of a couple dollars a month.

If you have some really old fridge made in the 1970's or before that has
not died yet, find out how much electricity it is consuming, then
determine a rate of return from replacing it. There is some chance that
could exceed the long term rate of return of a good mutual fund,
especially considering that electricity costs are likely to increase
roughly with inflation in the next decade or two.

- Don Klipstein )

In article , mm wrote:
On Sun, 17 Jun 2007 14:46:43 +0000 (UTC), (Don
Klipstein) wrote:

In article , Michael A. Terrell wrote:
Don Klipstein wrote:

In article , Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein )

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

Part of the thread is in alt.home.repair AND sci.electonicts.repair.

Another part is only in ahr.

I think I brought in ser, and the answers about wall warts are in the
other part of the thread.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

You read ser iirc. So it's not that your server is screwy or that you
failed to notice.

There is almost always a third possibility, even though often people
(I'm not referring to you) don't want to believe it (Either it's
amnesty or it's deportation)

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

OH, I should have read this sentence first. OOPs. To find the posts
in ahr, you should come with the subject name and the date, because
there is so much traffic on Ahr that it will be hard to find
otehrwise. Or use groups.google and the exact subject name.

I was reading ahr. I could have glanced too quickly through a range of
subject lines towards the end of the alphabet. I scan through subject
lines more carefully in the range starting with "C", "F" and "L" since I
pay more attention to lighting and fluorescent lamps than to most other
stuff that comes up in ahr.

- Don Klipstein )

On Sun, 17 Jun 2007 21:21:56 GMT, M Q
wrote:



I will repost here once I have remeasured with real power numbers.
(don't hold your breath -- it may be a while).

I'm going to hold my breath. If you don't see me posting, it's
because I've passed out, probably right in front of the computer.
Please notify the emergency number in my Bigfoot or Yahoo profile.

On Sun, 17 Jun 2007 18:04:34 -0400, mm wrote:

On Fri, 15 Jun 2007 15:09:42 -0500, "dnoyeB" wrote:

On Wed, 13 Jun 2007 14:51:20 -0400, Zephyr wrote:

Hey folks,

I'm curious about power consumption of things like the power supply
for my dell laptop
its and AC/DC adaptor, and when the unit is charging my laptop it gets
quite warm.
from that I infer that its using a fair amount of power.


traditionally, transformers do use power even when their device is not
on.
There is loss in the field. But more modern electronic ones do not
require anywhere near as much. Recent cell phones I think are
electronic transformers. Those I tend to just leave plugged in, LED and
all!!

It's probably hard to tell the modern ones from the older ones. They
all have cases made of plastic, which is the only clue I usually get for
"new".

I've taken apart some of the almost cube=shaped plastic ones and all
they have inside is a metal core transformer and, rarely and for big
ones, a fuse wire. The big ones get less hot because they spread the
heat over more area.

Is 2 to 2.5 cents per 24 hour day not worth worrying about? 2.5 cents
is 9 dollars a year, times however many of these one has. Maybe 10? =
90 dollars a year, plus 90 dollars of wasted electricity and fuel at the
electric generating plant, plus half of year as heat that people use AC
to remove, another 90 or 180 dollars.

Not that I unplug everything. It's easy enough to do so where the
receptacles are handy, but where they are behind the bed, or behind the
bookshelves, not so easy.

electronic ones tend to be much smaller and thinner. But not
necessarily.,