a [SMTP:gui...@cae.com]
> Sent: Tuesday, January 08, 2002 8:57 AM
> To: 'Carmen.Filimon'; 'EMC Forum'
> Subject: RE: SMPS Derating reqs for Altitude range of 5000-1ft
> Importance: Low
>
> As mentioned by some colleagues in this forum, some therma
As mentioned by some colleagues in this forum, some thermal effects due to
altitude are caused by reduced air density, which decreases the heath
dissipation through convection.
The percentage of heath dissipation by convection depends of the
construction of each power supply (I don't believe most
While the question and discussion related to SMPS, and brought up
spacing and cooling issues, you might also consider the rest of the
system.
Disk drives in the past have had altitude problems due to flying height
of heads. I assume this is still an issue since technology is always
pushing the l
Hi Chris, Andrew, Carmen:
With regard to safety, both effects of altitude
must be considered:
1) effect of air pressure on the electric
strength of air (clearance), and
2) effect of lower density air on the
temperature of solid insulation.
(Creepage is a surface
MTP:acar...@uk.xyratex.com]
> Sent: Friday, January 04, 2002 12:59 PM
> To: Carmen.Filimon
> Cc: EMC Forum
> Subject: Re: SMPS Derating reqs for Altitude range of
> 5000-1ft
>
>
> Carmen
>
> If your power supply is approved to IEC60950, then normally i
:59:15 AM
Please respond to acar...@uk.xyratex.com (Andrew Carson)
Sent by: owner-emc-p...@majordomo.ieee.org
To: "Carmen.Filimon"
cc: EMC Forum
Subject: Re: SMPS Derating reqs for Altitude range of 5000-1ft
Carmen
If your power supply is approved to IEC60950, then n
>From the Paschen curve, the electrical spacings must be increased 14% at
3000 meters over those at 2000 meters. Thermal derating is a tougher call
since some smps vendors engineer in more cooling capacity than others.
Testing for your application is the only reliable way to make a good
determinat
Carmen
If your power supply is approved to IEC60950, then normally it will be approved
upto 2000m. Above this altitude the
required creepage and clearance distances start to increase. It is an
electrical insulation issue, not a thermal
issue.
"Carmen.Filimon" wrote:
> Hi All
>
>
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