Power Strip Liberator
I believe this product has been mentioned before
in the newsgroups. It's good enough that it bears
repeating. It is a ~1' long extension cord, that
allows you to plug a wall wart in without covering
other outlets on your power strip. You can have your
DSL modem, router, amplified speaker and whatever
else all plugged in to a strip, with the other strip
receptacles still accessible. Cyberguys (link below)
sells them, as well as other places.
http://www.cyberguys.com/templates/searchdetail.asp?productID 57
Ed
Personally I prefer the surge protected strips sold by the local Focus DIY
store in 4 or 6 way strips for £8/£10 respectively, both the PC desk and TV
stack have them, I consider the regular 2meter lead to be a useful addition
of common mode inductance. If the wall-wart adapters crowd the plugs out, I
just buy more surge protected strips and increase the protection.
I simply put in a whole-house filter and surge arrest system at the
consumer unit. It is bonded to the protective earth at that point. I
also have an online UPS, feeding its own ring main.
But then, my mains electricity comes on poles across Dartmoor.
Makes sense, but I have a totally different take on it.
Why not settle for some kind of common standard that means manufactures
can't exploit the public with high-cost warts of unusual voltage, polarity,
whatever they can do to make their wart vital and another wart useless?
Given the amount of warts, and the amount of waste that results when they
are not needed, isn't it time some standard was set? Governments are
breathing down the necks of business, urging restraint in consumption. If a
standard were made, people would get used to a single outlet with maybe 5V
and 12V and a slightly different conenctor for each, like the DC jacks with
2.1 mm or 2.5 mm plugs. Imstead of warts, there's by small cables and
plugs, cheap and standard, and a single strong PSU with a meter that let
the user know if they were taxing it too much. It would always outlast the
products it drove, and the product could always be plugged into a similar
PSU anywhere.
In short, co-operation is better than conflict if waste is to be avoided.
The electronics world is full of successful standardizations like mains
voltages, plug shapes, MIDI and other protocols based on specific
connectors and signals. Sure, there are also obvious incomptibilites, but
compared to those, the wall wart situation is a disgraceful rabble.
I usually avoid them by buying stuff that will take an IEC mains connector.
When I can't avoid them, I look for 12V or 5V capability, DC, postive on
centre pin. If it won't take that, then the only way I'll buy it is if
there is no alternative, and sometimes I'll modify it so it CAN use a
standard PSU I have lying around, so I can avoid relying on something that
is usually tatty, feeble, and expensive to replace with exact type.
Most people would welcome a standard low-volt buss for home and office
wiring. It works for boats, cars, planes, trains, wtf does it not work for
houses? Obviously it can, so it should, and the waste dreck of plastic and
steel would visibly decline within months of establishing it.
/rant.
If you've been purchasing consumer electronics in the past few years, you'll
have noticed that 3.3V is becoming a popular regulated output voltage as well.
That's part of the problem: You'd really need to give people adjustable power
supplies from at least 2.5V-18V -- if not 0V-48V -- and get everyone to agree
on the "programming" standard that sets that output voltage. (Granted, it
could be as simple as a resistor.... although as soon as you let some
committee work on it, they'll come up with something fancy like PoE, which --
usually -- works well and is -- reasonably -- cheap due to all the logic being
in a single IC, but it's actually a rather complex protocol for what's
inherently a simple idea... it often adds $10+ per Ethernet port on a switch!)
Another problem you have is... who's responsible if a product dies due to
being fried? Could you ever demonstrate that it was the "universal wall wart"
that fried the device if said UWW appears OK now? Even if you could, do you
think the UWW manufacturer is going to replace the $200 media box it just blew
up? Of course not.
If you've been around awhile you're familiar with the old Tektronix TM-500
series mainframes -- a large part of the attraction was the single power
supply being shared by all the plug-in cards. Why did TM-500 go away? One
significant reason was that the power supply started becoming a smaller and
smaller cost of the product -- these days you can get a 40W Chinese import
switcher for <$10 in quantity.
[Cough!] Done much world-traveling lately? I'm thankful that most switching
power supplies are now universal input (90-240VAC).
Yeah, you have a point, but I think that "solving" the problem is
significantly harder from a political point of view than you might think.
There are -- or at least were -- small businesses that cater to RVers and
truckers that make their livings modifying equipment for 12V operation. I
have a suspicion that many of them have gone out of business due to the
proponderence of cheap 12V-->120V inverters, though (you can get something
like a 300W inverter for <$20, and while it's utter junk, in many cases it
works just fine).
Most people are utterly clueless about this sort of thing.
It doesn't really... cars are 12V, yes, but other vehicles are 24V, 48V... the
IEEE wants cars to transition to 42V... older vehicles were 6V... so there are
always going to be more "standards" than you might prefer.
To a certain extent I think this problem slowly is fixing itself, no
government intervention needed -- people do seem to have a preference for
power supplies that don't block adjacent ports on a power strip, and I believe
a significant number will buy the product with the small switcher (that
doesn't block the next port) over one with a traditional (linear) wall-wart.
---Joel
No-one knows more about the exact power requirements of a product than the
people who build it, so for special needs they can add internal regulation.
This is usually done anyway. There's not much difference between 3.3 and
5V, just a little extra heat dissipation in the regulator when fed by 5V.
I don't agree about the adjustable type. The point of standards is to try
to remove the need for that, just as Joerg and others seek to remove the
need for a product to be shipped with preset pots in it. Good design to
established standards will reduce waste energy.
Ideally, its maker. The mains supplier isn't responsible for repairing a
110V unit plugged to 240V. Same logic applies. Also, up to a point, the
user should be responsible. If a unit intended for a 5V buss is regulated
with thermal or overvoltage protection, then plugging it to a 12V buss
would make it shut off periodically and annoyingly, or perhaps do something
more appropriate to warn the user to plug to a lower volt buss. Users would
generally know that if in doubt, plug to the low-volt buss first.
Connectors should be different for each buss, eliminating this risk.
This cheapness of SMPSU's allows devices to have their own regulators in.
Unlike linear types, it might not even matter which low-volt buss it's
plugged to, or even if it's AC or DC, if it has rectification and smoothing
built in. As this is no more than the effort and cost put into most warts,
this ought to be doable. (I'd suggest a DC buss system though, things
needing AC specifically are rarer and might best use their own
arrangements).
Not much. :) This universal input thing IS a big step in the right
direction, for sure. It will make it increasing painless to adapt to common
standards in the future. If products needing low-volt DC input also had
more of this, the standard low-volt buss becomes more feasible too.
Yes. Which is why I'm saying this to engineers not politicians. If the
politicians end up enforcing unenforcibles because the industry can't reign
in its conflict-induced waste, things will be worse, not better.
As a business like that is answering a need, it proves the need exists. I
could rest my case right there, but that would be boring. >:)
Going out of business as you describe means the need just got answered
differently. All that's happening is conversion to ANY standard buss, at
whatever cost. That's not just a need, it's a roaring demand! So there's a
new motive, profit. If that doesn't make the industry sit up and watch, and
think, what will?! They're small businesses, so I guess that's why. Most
big things start small though. If the thing were addressed so it's easy for
most people to get, it would grow enormously.
Only because no thoughtful, simple standard exists. If the industry isn't
willing to at least try, you can't blame the end consumer. Judging by the
number and type of inquiries that clog the queues of Maplin and Radio Shack
type stores, the consumer is really trying to find a way, and they are NOT
being helped adequately. Maybe it's time they were given a simpler choice
when they need to find sensible power supply and connector arrangements.
Agreed, but if the product has its own regulation for anything other than
standard 5V and 12V (the most commonly used in domestic locations), and
protection against plugging to a higher voltage, then it will work.
The question is which volts to standardise, and how many voltages. I'd
suggest a maximum of three (24V, 12V, 5V), ideally just two (12V and 5V),
because the biggest demand for clean DC voltages between 12V and 24V are
for analog IC's. These are usually small-signal devices, or have their own
mains supplies built in, and in either case, benefit from additional local
supply cleaning anyway, so a tiny power converter running off a 12V buss is
fine.
Almost all things of 5V and lower can run off 5V, with linear regulation or
power converter on very small scale. Many things are designed to run on 5V,
so it's extremely easy to adapt to. Same applies to 12V, hence my choice.
6V and 9V are common, but 9 is easy, regulate off 12V. 6 is a tad harder,
some things might need the 12V and waste a bit, most might be able to run
on 5V well enough.
Higher voltages like 48V are worth making a special case for, but it's just
a variant on the same idea. In small cluttered places like homes and
offices, few things demand voltages that high, and those that do either
have their own mains inputs or can be made to work on 12V with a small
power converter built in. As a wound transformer might cost more, it's
worth doing. It's more efficient too.
I'd hope that no government intervention will happen at all. But with the
current pressures being put on industry, can you imagine they won't?
They're already wreaking havok with CO2 emissions controls, and the sudden-
ness of the demand to phase out the use of lead. The problem is fixing
itself because it must.
I'm only pointing out that trying to accomodate wall warts on a purely
physical basis is the wrong way of looking at the problem. Most switchers
for public consumption seem to be 5V or 12V output, unless you buy for
something specific. This is good, it's as you say, part of the self-fixing
effort the industry is making. All I'm saying is, why not go further, make
more powerful ones, standardise connectors per voltage, NOT on some
arbitrary way to make firm A's wart useless for B's product. That way the
end user buys one per room, and anything in that room will plug into it.
There are better ways to bring heads together than waiting for government
to bang them together.
A problem with a common supply is that often the gear is connected
together and also shares a common signal ground. You will get nasty
problems with ground loops, never mind the disasters of having some
devices run on positive rails, and some on negative.
--
Regards,
Adrian Jansen adrianjansen at internode dot on dot net
That is true, BUT, if you look at any studio audio guide to best practise,
you'll know of the 'star network'. As this requires that there be a common
connection point for all supplies and grounds, a standard buss isn't the
cause of trouble is it? It's the only correct basis for a cure.
Solving of grounding problems per device is required, just as an end user
should not be expected to break a safety ground to solve suck loops. It's
the maker's problem. Again, if they knew there was a standard, they'd know
what method of ground-loop prevention they'd need to use.
The polarity thing IS a problem, and a very nasty one, too, but I've rarely
seen a positive ground in a device that didn't do it either out of
convenience, or an attempt to deny the use of a more standard supply. Just
because arbitrary choices have been made, is no reason to ignore the
problem. They MADE the problem, so exonerating the people who made it as if
they have the last word is going to be counterproductive. Fortunately the
positive-centre-pin is begining to win out. Personally I don't care which
had won, as electrons flow from the other pole, but as the worst risk of
damage is reverse polarity, this problem needs standardising ASAP! In the
meantime, we can always use diodes. >:)
People seem to be using the USB connector as a 5V bus, and usually they
blatantly ignore the current limit specification too...
Ground loops are certainly a problem even now - my laptop has an external
power supply which has an earth pin on the mains cable, and the negative
terminal of the DC output of the SMPS is earthed at the power supply. With
about 3 Amps flowing in the negative wire of the DC cable from the power
supply to the laptop, the ground of the laptop is at about 50-100mV above
mains earth. This voltage changes when the CPU or hard disk does
something. When I plug the audio output into an external hifi amplifier
with its own mains earth connection, all sorts of nasty sounds come out of
the speakers because the laptop's ground is not at the same voltage as the
amplifier's ground (and a couple of amps are flowing through the ground of
the audio cable).
What would be much nicer would be a power supply for the laptop with no need
for a ground connection to the output side, and ideally something similar
for the hifi.
Since cables from your multi-wart are going to drop a significant amount of
voltage anyway, I think it is not useful to attempt very close regulation
of the output voltage. In that case, it might be quite feasible and cheap
for each output of the multi-wart to be floating with respect to all of the
others, since all of outputs could be derived from separate secondary
windings on the SMPS transformer. If it is a small flyback converter, each
winding would need a diode and a couple of capacitors, and the regulation
could be based on just one of the outputs. Each output would not have very
good regulation (but cable will ruin the regulation anyway), and the
outputs would all be isolated, permitting people to ground whatever parts
they want without the power supply causing any particular extra problem.
Chris
-----------
Lets see. 12V DC wiring over what distances? In a car it appears OK but with
the increasing electrical loads in cars, there is serious consideration of
higher voltages for cars. In a house, or in other than small aircraft and
definitely not in trains- something like 12V is simply too expensive in
terms of material costs and weight. The problem is that to get something
sufficient to supply my computer, monitor, printer, scanner, speakers etc.
requires a dedicated circuit equivalent, in terms of wiring, to at least 3
standard 15A circuits (based on 180 watts at 15A, 12V). That is for
equipment located at one place and doesn't allow for devices elsewhere . You
will still need a converter and will also require more expensive circuit
breakers than 120V AC needs. There is also the problem that, for most of
us, with more existing house than retrofit funds, this centralized approach
is out of reach.
Note that mains voltage and plug standardization (or standardisation
depending on the countries involved) have nothing to do with "electronics"
standardisation except that the power utility standardizations determined
the sources that the electronics industry standardized to. Note that the
former "electronics" standardization of 117V (apparently +/- zilch) was a
fiction that led to poor designs that couldn't handle normal variations in
line voltage. The problem was resolved when it was realized by both
utilities and electronics designers that there were normal variations along
with one hell of a lot of crap coming in on the lines.
Maybe wall warts aren't that bad- admittedly standardization of plugs and
voltages is needed along with elimination of "in-between" sizes.
rant returned with another rant :).
--
Don Kelly snipped-for-privacy@shawcross.ca
remove the X to answer
10 feet? One per room, on average. Considering the stupid proliferation of
warts that is why this thread even exists, that seems like a good scale to
work with. The total wiring thickness and length on that scale would be no
worse than the wiring currently bringing low-volt lines out of those warts.
Most of them are in one location, concentrated near a hi-fi or a computer,
or a bed. People like to organise when things get out of hand, especially
when the disorder is always in close proximity.
The 'buss' need not be any bigger than a mains 4-way plug strip. You could
fit a 200W PSU and lots of connectors on that, with a cost below £25, which
given the wart count reduction, is a good spend.
I agree with you about cars though, a lot of high currents there, it would
save a lot of metal in switches and wires to use 24V. More is NOT a good
idea. In a crash, there's enough deal with without adding electrocution.
This is my rant. There are others like it, but this one is mine. >:)
Thank you, I had the impression that you were talking about a whole house
system. I assume that the room unit will be regulated as load could vary
widely. If not you could have problems which don't occur with equipment
which comes with its own wall wart designed for that particular apparatus.
--
Don Kelly snipped-for-privacy@shawcross.ca
remove the X to answer
Yes, as I said (in other posts), regulation of 5V and 12V busses would be
done. I doubt they'd have to be done independently. Devices that want other
voltages or very clean supplies would also have their own regulation.
The only specifically new part of the idea is the elimination of warts and
the waste associated with them, acheived by standardising buss voltages and
polarity, ideally positive centre pin as that's become a dominant standard
now. Things like ground loops and noisy signal lines can all be cured by
current good practise.
The idea is not in conflict with many good practises, if any, it's only the
adherence to bad ones that perpetuates problems. Most successful hardware
protocols are those that were established before counterproductive
conventions could trouble them. This one could still succeed because of the
increasing number of small low-volt devices. A sprawling mains buss is
awkward and dangerous, and a few house fires will dramatically hammer home
the truth of this false economy to a public that will then buy eagerly from
whoever is making a safer alternative.
Greetings,
Liberators:
Yes, they are handy. Be warned, however, that not all are UL listed.
(AFAIK, the ones I purchased some time ago from Cyberguys aren't,
sigh, but the new ones seem to be.) They also may be available from
your local drug/hardware/misc store. I believe I saw some under the GE
brand, but I'm 100% sure the only connection GE has with them is in
sticking the GE name on them.
Outlet Strips:
I recall reading that surge protected outlet strips in plastic cases
are responsible for quite a few home fires each year. I also don't
believe that UL listing is as strong a guarantee of safety as one
might hope. Anyone considering purchasing one -- especially one of
those high-priced, brand name designer pieces of Chinese cr#p --
would, IMHO, do well to consider purchasing a Wiremold "Perma Power"
unit instead (Manufacturer (Wiremold): http://tinyurl.com/2dcp8c ; one
distributor (Mouser): http://tinyurl.com/yno2f7 ) They cost no more
than the Chinese units, but are (were?) USA made.
Cordially,
Richard Kanarek
wrote:
When MOVs fail they can overheat. In 1998 UL changed its standard (now
UL1449 edition 2) to require overheating MOVs be disconnected.
Connected outlets may be disconnected with the MOVs or stay connected
without protection - the protector should say which option is used.
--
bud--
It's $2 plus shipping. I can buy an extension cord with three outlets at the
dollar store. That lets me hook two or three warts to one outlet for $1
instead of $6 plus shipping!
With that money, I can get 5 plugs and five females and 5' of cable and make
myself 5 "liberators".Nice idea,though;-)
(I have a simple, 5 euros switched wall-wart so that none of my gear is
under voltage when not in use).
--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
dimtzort AT otenet DOT gr
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