Pete, I definitely agree with you on your points about experience. It seems the highly experienced ones are those who are most successful on first pass EMC testing. You can often tell who these people are on the design team by the number of war stories they can tell. I sometimes think of this in the same way as parenting. You can read all the books and get all the advice, but it seems getting your own hands-on experience is the key.
-Doug Douglas E Powell Laporte, Colorado USA doug...@gmail.com http://www.linkedin.com/in/dougp01 On Mon, May 24, 2021 at 11:20 AM Pete Perkins < 00000061f3f32d0c-dmarc-requ...@listserv.ieee.org> wrote: > Charles, et al, You question is rather simplistic, in my opinion. > > > > From my more than 25 years doing safety & regulatory > consulting with dozens and dozens of companies both large and small, I find > that the experience of the design team is the key to meeting the > requirements early on. > > > > First timers (no prior experience having an outside lab > test any of their work for compliance) has a pretty low pass rate; no > matter how much advice is given during the design phase. > > > > Design teams quickly gain experience ramp up & meet > compliance requirements on the next project or two providing the design is > similar to their earlier experience. > > > > This level of competence can be confounded (made worse) if > there are substantial changes in the design team between projects. Newbies > always think they understand the needs and design accordingly; unless an > experienced team manager can ferret out the issue before testing and get > them to change. > > > > Additional features (especially radios) complicate the > issue, even for experienced design teams. > > > > To specifically answer your question, first designs from an > inexperienced design team generally will need another pass (or more) thru > the lab to qualify. Experienced teams will have a high 1st time pass > rate in most cases. > > > > To relate one scenario, a complex electronic research > instrument was developed by a 3 man team of PhD physicists who struggled > when going thru the EMC lab; they had no prior product certification > experience. I had offered to go to the lab with them but they thought they > could handle it themselves. They had no concept of the needs to provide > the proper isolation between major pieces (e.g. cables routinely pierced > the chassis and made connexion well within the equipment). After the 2nd > failure the lab manager, a long-time colleague, talked to me and said that > they weren’t listening to his comments about needed changes to fix it. > Upon talking to them, they had dismissed him as just a technician (ignoring > his EE training and EMC lab experience) and they believed that they knew > better (but not good enough, as evidenced by the continuing failure). So > we had a ‘managerial discussion’ and I went to the EMC lab with them from > then on. The baling wire fixes tried at the lab showed improvement when > applied and led to installing proper connectors at the chassis interfaces > along with some other changes; it finally passed. > > > > Others probably have more interesting cases to relate, > too. > > > > Does that fit with your experience? > > > > :>) 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 > > www.researchgate.net <http://www.researchgate.net/Peter%20Perkins> search > my name > > p.perk...@ieee.org > > > > > > Entropy ain’t what it used to be > > > > *From:* Grasso, Charles [Outlook] <charles.gra...@dish.com> > *Sent:* Monday, May 24, 2021 7:47 AM > *To:* EMC-PSTC@LISTSERV.IEEE.ORG > *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? > > > > > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > emc-p...@ieee.org> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > emc-p...@ieee.org> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > -- Douglas E Powell doug...@gmail.com http://www.linkedin.com/in/dougp01 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
