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[email protected] stratus46@yahoo.com is offline
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Default Why do some manufacturers wrap the electrolytic capacitor thatgets the hottest in a switching power supply in shrink wrap?

On Aug 30, 2:48*pm, Jim Yanik wrote:
Chuck wrote innews:

:

Extron has been doing this for years and of course it is the

first
part to fail in their units. *Smart Technologies Sympodium power
supplies, that they have contract built in China, fail in a year

or so
for the same reason. *Technicians and electronic engineers at my

work
place can't think of a rational reason why these manufacturers do
this. *This is pro gear where reliability is a great concern so

it
doesn't seem to be planned failure mode. *Thanks. *Chuck


IMO,in a proper design,the caps should not be getting hot.
Caps should be sized and rated properly,with a fair amount of

excess
capacity,not sized/rated right at the margins.
We have inexpensive thermal imaging available that can identify hot

spots
so that they can be corrected before the design is finalized.

--
Jim Yanik
jyanik
at
localnet
dot com


The caps may not be getting hot on their own but get damaged from
nearby hot items. We had 16 Samsung digital tuners at work that had 1
cap that fails next to a diode on a heatsink. We replaced it with a
very good grade cap but extended the leads just enough to lay the cap
on its side away from the heatsink. Luckily room to do that existed.

G