I've really only been able to use these to demonstrate utility and
justify another board spin. Forget about them in aviation use; they can
stop working after one vibration test --- not that anyone with
experience would expect more.
When I was at Alcatel USA in Petaluma -- before Telecom Valley died and
blew away -- I spent a lot of time poring over design files in R&D,
with the objective of making problems go away before metal was bent and
boards fabricated. That's where we really earn our pay -- if we're
allowed to.
And if I'm ever interviewed for a full time position again, I'll ask to
see the "lessons burned" files.
Cortland Richmond
On 8/14/2018 4:31 PM, Edward Price wrote:
*Ken:*
**
*I had some experience with using multiple EESeal connector EMI
filters on a complicated Navy data telemetry system. One interesting
thing about using these EESeals was that they made contact to each pin
within a connector by having one or two tiny, thin gold leaf tabs
extend from the EESeal silicon rubber “sandwich.” When all the
connector pins were in perfect alignment, and the EESeal was installed
perfectly into a connector shell, the connector pins would firmly
press those little gold leaf contacts against the EESeal’s hole ID.
This made a good, low-impedance connection between the connector pin
and the EESeal’s capacitor chips. IIRC, the EESeal body also had
several little gold leaf tabs on its OD, in order to make a ground
connection to the connector shell.*
**
*I mention this in some detail because I found that when the connector
pin alignment wasn’t perfect, or the EESeal wasn’t inserted nice and
flat, it was possible to stress the little gold tabs. If you got an
EESeal in place and then removed it (using Quell’s approved method),
you might (due to cost) be tempted to reinstall it later. I found that
a microscopic examination of the EESeals sometimes disclosed missing
gold tabs, or sometimes they had been “balled up” against the hole ID
wall. My point is that these are fragile components, and there is a
possibility of misaligned gold tabs or even broken tabs being trapped
between the connector insulation face and the EESeal silcon rubber
body. This certainly frightens me from a reliability standpoint, as
you can’t see this from any visual examination of an installed EESeal.*
**
*The installation of EESeals (the tiny ones were more troublesome than
the big, multi-pin ones) must be done by tech’s who understand the
weaknesses of these marvelous gadgets, and who are willing to reject
an assembly rather than “make it fit.” And from an engineering
viewpoint, your quality assuarance should cover the possibility of
degradation arising from installing this type of device.*
*/Ed Price
/**WB6WSN**/
/**Chula Vista, CA USA*
*//*
-----Original Message-----
From: Ken Javor [mailto:[email protected]]
Sent: Tuesday, August 14, 2018 7:37 AM
To: [email protected]
Subject: Re: [PSES] X & Y Cap rating due to hipot test
No one knows about the eeseal. It's a possible EMI fix. I don't know were
the 1000 V hipot test came from; I supposed it was insulation
resistance/creepage-based. The point is, it is a dc requirement and the
device will never see 1000 Vdc elsewhere, therefore it seems like an
inappropriate requirement to place on a cap as a WVDC rating, and I don't
see why it should be placed on an EMI filter external to the EUT.
Ken Javor
Phone: (256) 650-5261
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