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Posted by Siggy on April 8, 2006, 4:35 pm
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A while back there was a discussion about why wall wart transformers that
were not under load would draw no current. Anyone recall that thread? As I
recall there were some references to the induced currents created by
collapsing magnetic fields etc.
Anyway, I'm trying to either prove or disprove the statement that unplugging
wall warts when not actually using them to power or re-charge your device
will save electricity. My recollection is that it doesn't matter. Right or
wrong?
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Posted by Leon on April 8, 2006, 4:48 pm
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Siggy wrote:
> A while back there was a discussion about why wall wart transformers that
> were not under load would draw no current. Anyone recall that thread? As I
> recall there were some references to the induced currents created by
> collapsing magnetic fields etc.
>
> Anyway, I'm trying to either prove or disprove the statement that unplugging
> wall warts when not actually using them to power or re-charge your device
> will save electricity. My recollection is that it doesn't matter. Right or
> wrong?
It will save a little, but you won't notice it. Manufacturers usually
recommend unplugging them when not in use, for safety reasons, as they
can be a fire risk if they develop a fault.
Leon
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Posted by Jim Stewart on April 8, 2006, 4:59 pm
Please log in for more thread options Siggy wrote:
> A while back there was a discussion about why wall wart transformers that
> were not under load would draw no current. Anyone recall that thread? As I
> recall there were some references to the induced currents created by
> collapsing magnetic fields etc.
>
> Anyway, I'm trying to either prove or disprove the statement that unplugging
> wall warts when not actually using them to power or re-charge your device
> will save electricity. My recollection is that it doesn't matter. Right or
> wrong?
Iron losses are constant for all loads including none.
Copper losses are proportional to the load.
You will save the energy used by the iron losses. Whether
this is enough to make more than a few cents difference
in a year is the question.
Assume 1/4 watt loss and $.20/kw.
(1/4 / 1000) * 24 * 365 * .20) = $0.438 per year.
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Posted by Nick Hull on April 8, 2006, 5:14 pm
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> A while back there was a discussion about why wall wart transformers that
> were not under load would draw no current. Anyone recall that thread? As I
> recall there were some references to the induced currents created by
> collapsing magnetic fields etc.
>
> Anyway, I'm trying to either prove or disprove the statement that unplugging
> wall warts when not actually using them to power or re-charge your device
> will save electricity. My recollection is that it doesn't matter. Right or
> wrong?
>
>
Just put your hand on a plugged in wall wart; it will be warm. that is
the power it's wasting; some but not much.
--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/
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Posted by Jon Elson on April 8, 2006, 5:26 pm
Please log in for more thread options Siggy wrote:
> A while back there was a discussion about why wall wart transformers that
> were not under load would draw no current. Anyone recall that thread? As I
> recall there were some references to the induced currents created by
> collapsing magnetic fields etc.
>
> Anyway, I'm trying to either prove or disprove the statement that unplugging
> wall warts when not actually using them to power or re-charge your device
> will save electricity. My recollection is that it doesn't matter. Right or
> wrong?
>
>
Does it get warm whel left plugged in with no load? If so, it IS
wasting electricity. It may not be a whole lot, possibly you can feel
loss of less than a watt. And, it can't be a whole lot, as those
little plastic cases can't dissipate more than a couple watts without
getting VERY warm.
A very high quality transformer can be very efficient. But, the stuff
they put in a wall wart is NOT going to be high quality. So, if it gets
warm, that is absolute proof energy is being wasted.
Jon
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> were not under load would draw no current. Anyone recall that thread? As I
> recall there were some references to the induced currents created by
> collapsing magnetic fields etc.
>
> Anyway, I'm trying to either prove or disprove the statement that unplugging
> wall warts when not actually using them to power or re-charge your device
> will save electricity. My recollection is that it doesn't matter. Right or
> wrong?