So the small benefit of these new power siupplies should be weighed
aginst
1) greater complexity
2) lower reliability
3) greater EMI
4) potential fire hazard?
5) potential shock hazard
If these switching supplies fail at even a slightly higher rate and
cause a few people to take a few extra rides CAR rides to get
replacements then the small energy savings will all be lost...
Legislaters and politicians are not smart enough to be making these
decisions for us...
Further investigation suggests it is indeed an Australian thing and
applies only to *external* power supplies. I'd be happy to say goodbye
to wall warts and lumps in a cord myself.
Mark said:Legislaters and politicians are not smart enough to be making these
decisions for us...
Phil said:"Eeysore"
** God knows what it is.
It don't say.
Nor is there proof of class 2 compliance.
Anyone can use the double square symbol, at whim.
For the benefit of us yanks, what does pommy mean?
Normally, they tend to consult "experts" first.
One problem there is
that the obvious experts would be people who design and manufacture PSUs,
I'm 100% confident Toroid apply it correctly.
Terry said:Thats very likely the case - if he behaved like that in public, he would
be beaten senseless on a regular basis.
Michael A. Terrell wrote in said:Is there no Ex-Lax, down under? These, and other
questions will be answered on the next episode, of "Australia's Most
Pathetic Troll' so stay tuned to this channel for the next exciting 9?)
episode of our programe.
Don said:I wonder if the one this makes me think of has any association with an
even worse sub-troll from Australia, who has "earned" a FAQ that says he
is not worth a FUQ, well below the other juvenile that changes names a few
times a year now.
I suspect less likely, since the supreme Australian sub-troll appears to
not get along with much of anyone but likes to tick people off.
- Don Klipstein ([email protected])
Winfield said:The cost of making the changes I see necessary is not zero,
but it's quite small, perhaps 20% at most.
Let's assume a billion of these transformers with a $.1 cost increase.
So it really does make sense to improve the efficiency of small
applicances from an economical standpoint alone.
The same argument could be made from the consumer's point of view: The new
wall wart consumes 1W less, which (assumed it's on 24/7) will save about
1.7
EUR/year (in Germany). Such amounts of money are too small to make any
appreciable difference to the consumer, so we can't rely on the market
forces having any effect. Government intervention is the right thing to do
here.
Robert said:["Followup-To:" header set to sci.electronics.design.]
Winfield said:The cost of making the changes I see necessary is not zero,
but it's quite small, perhaps 20% at most.
Let's assume a billion of these transformers with a $.1 cost increase.
That's $100m the consumers will have to spend.
But all those transformers will consume about one gigawatt less, that's the
equivalent of a normal power plant.
So, essentially, you get 1GW of power for $100m. That's pretty good, plus
this "virtual power plant" doesn't consume any primary energy nor has it
emissions. So it really does make sense to improve the efficiency of small
applicances from an economical standpoint alone. No pants peeing greenie
weenie arguing required here.
The same argument could be made from the consumer's point of view: The new
wall wart consumes 1W less, which (assumed it's on 24/7) will save about 1.7
EUR/year (in Germany). Such amounts of money are too small to make any
appreciable difference to the consumer, so we can't rely on the market
forces having any effect. Government intervention is the right thing to do
here.
Phil said:"Robert Latest"
** Completely WRONG.
Iron core transformers in external PSUs are about to * disappear * - you
ASS.
The REAL cost increase to the public may well be horrendous.
http://sound.westhost.com/articles/external-psu.htm
The increased electrocution risk alone is TOTALLY unacceptable.
Phil said:http://sound.westhost.com/articles/external-psu.htm
The increased electrocution risk alone is TOTALLY unacceptable.
Next I used a DP-241 size-4 frame part. This fellow was
nearly identical, but had the primary winding broken into
two portions so they could be wired in parallel for 120V,
or in series for 240V operation. My thesis was that the
primary should have more turns to meet the new rules, and
a factor of two seemed reasonable. To test this idea I
ran the 240-volt transformer wiring on 120 volts.
Now I measured only 5.5mA peak primary magnetizing current,
more than 10x less! Note that's only 0.66 VA. Clearly the
primary magnetizing fields were well below the dangerous
power-wasting saturated region. The current-voltage phase
shift was about 45 degrees. Are you ready? The new power
consumption was, tada!! 0.40 watts.
That's well under the new allowed limit. And I think with
further design optimization they can do even better.
So I predict the transformer manufacturers won't have any
trouble making parts to meet the new rules. I for one will
be glad to see it and look forward to buying the new parts.
Winfield you are so rigth!
It is very possible to make small transformers with < .5W loss
if good iron quality is used, and sufficient turns....
We had some of those made locally already many years ago (30? ;-)),
did not even get a bit warm.
Iron quality is _very_ important (and sufficient iron) to get
a low loss.
There are several sorts of iron to choose from IIRC (my first
job was in a transformer / power supply company).
No problem.
Actually a good idea, as most of these little buggers get way too hot.
Winfield said:In his web document, "The Humble Wall Transformer is the Latest
Target for Legislators," By Rod Elliott (ESP), Rod states,
"A mandatory energy rating requirement effectively bans all
presently available transformer based external supplies
because their magnetising current is higher than allowable.
In order to pass, the no-load dissipation must be less than
0.5W for supplies rated at less than 10W, or 0.75W for
supplies rated at between 10 and 250W. Most small
transformers draw a magnetising current of around 20-30mA,
and the range of power consumption I measured was between
1.1W up to 1.8W (this was verified with a fairly wide cross-
section of supplies at my disposal. The dissipated power is
directly related to the winding resistance, and also includes
iron loss - that amount of power needed to reverse the flux
in the core on each half cycle of the AC waveform)."
In my opinion, Rod is badly misinformed on this issue, and
perhaps by extension in his reading, then so would be Phil.
It's too bad Rod didn't consult the extensive discussions
some of us have had here on s.e.d., wherein we listed some
detailed measurements of small transformers - magnetizing
inductance, leakage inductance, dc and ac resistances, etc.
We found that typical manufacturers make rather efficient
transformers when they're making larger models, but when
they make small ones, e.g. 2.5 and 6VA, they really take
serious liberties saving on the relative amount of copper
and iron used. This allows the little buggers to dissipate
far more heat than necessary, compared to their size. We
speculated that they felt, hey, it's only dissipating 1.5W,
or 2 or 3W, so what's the problem?
It's trivial to greatly reduce the magnetizing current by
adding some primary turns and thereby staying much further
away from core saturation.
I performed a simple experiment with a Signal Transformer
241-series size-4 frame part. That's one size up from the
smallest size they make in that type. I operated without
any loads.
I measured the primary magnetizing current at 65mA peak,
which given our 120V ac power = 7.8 VA. Most of the
current was out of phase with the primary voltage, so
the power consumption was much less, about 1.23 watts.
Not too bad, and in keeping with Rod's measurements, but
oops! well over the new allowed limit.
Next I used a DP-241 size-4 frame part. This fellow was
nearly identical, but had the primary winding broken into
two portions so they could be wired in parallel for 120V,
or in series for 240V operation. My thesis was that the
primary should have more turns to meet the new rules, and
a factor of two seemed reasonable. To test this idea I
ran the 240-volt transformer wiring on 120 volts.
Now I measured only 5.5mA peak primary magnetizing current,
more than 10x less! Note that's only 0.66 VA. Clearly the
primary magnetizing fields were well below the dangerous
power-wasting saturated region. The current-voltage phase
shift was about 45 degrees. Are you ready? The new power
consumption was, tada!! 0.40 watts.
That's well under the new allowed limit. And I think with
further design optimization they can do even better.
So I predict the transformer manufacturers won't have any
trouble making parts to meet the new rules. I for one will
be glad to see it and look forward to buying the new parts.
Winfield you are so rigth!
It is very possible to make small transformers with < .5W loss
if good iron quality is used, and sufficient turns....
We had some of those made locally already many years ago (30? ;-)),
did not even get a bit warm.
Iron quality is _very_ important (and sufficient iron) to get
a low loss.
There are several sorts of iron to choose from IIRC (my first
job was in a transformer / power supply company).
Snipped to highlight a point....
I like the idea of SMPS which stop switching, and resume with output
load etc. - many idling SMPS make very strong signals at RF to 50+ MHz.
For a small signal radio listener to survive many of these supplies must
be turned off completely as they make terrible noise at HF and above.
Some make a broadband white noise and others a gurgling, swishing noise
which wanders all over the spectrum - worst offenders here are DVB-T
receivers and (especially) SAMSUNG colour televisions.
I turn all my SMPS and then I can hear those of neighbours...I hate
the stinking things !
