James,
You don’t have to denigrate yourself as not being a guru. You have plenty of
experience in this as shown by your comments. Sharing this is quite valuable
to the others on this thread.
All of us started out as ignorant of any of these requirements
because they are not taught in formal college level courses; a few exceptions
seem to exist.
Some folks might get specialized training – if they work for a
gov’t agency or a safety test organization; else it’s all OJT.
I don’t see that changing any time soon; the academic folks have
their interests which continue to push mathematical analysis techniques (and
that will continue). More and more technical folks will get higher degrees
[you know what BS is, MS is More of the Same and PhD is Piled higher and Deeper
:>) ], hardly any of which is of interest at our daily working level.
Manufacturers will continue to steal trained folks from test labs; probably not
too bad a deal especially if the folks move back and forth to spread what
they’ve learned going each way.
Finally, the standards keep getting more complex (PhD effect)
and interrelated as issues are delved into more deeply; plus manufacturers are
getting better trained to design near the limit without as much margin so the
compliance is close to falling off of the edge of the world at any moment.
So keep at what you are doing as long as you enjoy it; then get
out gracefully – keeping your reputation intact to maintain a legacy as you go.
Enough of Phil 101 today.
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 1067
Albany, ORe 97321-0413
503/452-1201
IEEE Life Fellow
IEEE PSES 2020 Distinguished Lecturer
<http://www.researchgate.net/Peter%20Perkins> www.researchgate.net search my
name
<mailto:[email protected]> [email protected]
Entropy ain’t what it used to be
From: James Pawson (U3C) <[email protected]>
Sent: Tuesday, May 25, 2021 1:19 AM
To: [email protected]
Subject: Re: [PSES] What percentage of products pass first time?
(replying even though I’m not a guru)
Hi Charles, hope all is well with you
Speaking from my own experience. Over the last four years of running a
consultancy, pre-compliance and low cost test EMC laboratory I would (very
roughly) estimate that around:
* 50% of products pass their desired radiated emissions limits without
any modification
* 33% or less pass all of the applicable tests first time without
modification
The major caveats and notes here are that
* These figures are for customers products where the EMC performance is
not known before testing. We do a lot of work helping people solve existing EMC
problems but we are not counting this in these figures.
* Most of my customers are smaller businesses that can’t afford to employ
an engineer to just look after compliance. That job role is either split
amongst several people or the engineer in question has to look after quality,
manufacturing, sustaining, thermal, system, and everything else. Speaking as
someone who has designed many products and systems in the past, trying to
design for functionality whilst simultaneously considering best EMC performance
is HARD. I use the metaphor of
* The products that pass first time generally fall into one of three
categories
* Products that we have design reviewed before the design was finalised
* Retests of products that have already been through our lab once
* Products that are very simple in nature
* Our hit-rate at being able to solve our customers problems is around
90-95%
* The “ones that got away” where we were unable to help deliver a
compliant include
* No action taken: Products where it was deemed by the manufacturer not
economically feasible to modify the product (e.g. product going end of life)
* No further communications from the manufacturer so we don’t get to find
out what happened next (no news is good news, right?)
I would echo the sentiments of others on this thread regarding the need to
design in compliance from the start.
One of the problems with the field of compliance is that it is too often
“learned through experience in industry” and not explicitly taught. When it is
taught at academic level it is often a surface treatment with a theoretical
look at shielding or maybe crosstalk with no other practical context or
background.
The split between industry and academia is one of the possible causes. Yes,
there are exceptions to this but they primarily remain exceptions. I had
discussions with a local university about some guest lectures on compliance and
the theme of the response was “it doesn’t really fit into any of our modules”
and “we can’t have it as an optional lecture as none of the students will
attend”.
The number of times I hear “oh, thanks for that. No one has every explained it
that clearly before” is worrying!
All the best
James
James Pawson
The EMC Problem Solver
Unit 3 Compliance Ltd
EMC : Environmental : Safety : CE + UKCA : Consultancy
<http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk | +44(0)1274
911747 | +44(0)7811 139957
2 Wellington Business Park, New Lane, Bradford, BD4 8AL
Registered in England and Wales # 10574298
From: Grasso, Charles [Outlook] <[email protected]>
Sent: 24 May 2021 15:47
To: [email protected]
Subject: [PSES] What percentage of products pass first time?
Hello EMC gurus!
Calling all labs - In your experience how many products pass the Unintentional
Emissions
test first time?
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