Subject: Re: Doubling wallwart power rating
Date: Mon, 7 Oct 2002 08:03:12 +0000 (UTC)
NNTP-Posting-Date: Mon, 7 Oct 2002 08:03:12 +0000 (UTC)
User-Agent: tin/pre-1.4-19990805 ("Preacher Man") (UNIX) (Linux/2.4.19 (i686))
N. Thornton wrote:
> "Phil Allison" wrote in message news:...
>> "N. Thornton" wrote in message
>> > Wall warts come in plastic cases, which must be very poor heat
>> > dissipators. If vent holes are added top and bottom, I wonder what
>> > sort of power out increase one could get.
>> > Anyone have an idea what sort of gains we might be looking at?
>> ** In practice - none. It must be allowed that wall warts are not
>> installed with any ventilation.
>> Also, I would not feel comfortable about one that was not small
>> object and water proof.
> Well, tell us why then Phil.
> I dont see how running cooler would make no difference to their max
> safe current delivery.
The 'knee' of the curve of power dissapated vs power delivered is
quite sharp for a transformer, as once the core saturates, BAD things
start to happen.
Wall-wart transformers are already run close to the edge.
With a resistor, you can sometimes get away with doubling the load current,
and adding a big fan.
A transformer will tend to either melt, or blow fuses.
> I can't offhand think of a scenario where a ventilated wall wart would
> become dangerous whereas a non vented one would not, in the same
> Why would wall warts need to be waterproof?
> Please explain :)
> Regards, NT
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