Re: [PSES] Brick power supplies and test errors (two topics)

[Douglas Smith]

Hi Ed and the Group, Ed said: "Did you create a write-up on what those errors specifically were, and how it happened that you noticed them in time to control them?" I have not specifically written them up although I do tell them as war stories during my presentations. The biggies I remember were antenna placement (we had a large EUT about 8 feet across), wrong antenna factors, and injecting more current in the conducted immunity test than was called for (they did not allow for lowering the current injected from the clamp to the value that would have resulted from the ISN into a 150 Ohm common mode load. The test person usually pushed back when I requested them to do the test differently, but when I had them bring the appropriate standard out, I was able to point to the applicable paragraph and they caved to my request. Other biggies are ESD test setups non-compliant (the lab test area) and the EFT test run with the clamp backwards. The clamp sends more energy to the AUX equipment than the EUT (I don't think the people who designed the EFT clamp understood how it works and did not bother to measure it either). So when backwards it sends 30 to 100 percent more amplitude of stress to the EUT depending on a few parameters. I have spend some time characterizing that clamp. Too bad it was not done by the committee before the standard was published. Since then, I have presented my data to the IEC committee responsible for IEC 61000-4-4, several years ago. But someone who goes to labs with no knowledge of how these tests are run are at a real disadvantage. Recently a customer of mine was given a passing test when it should have been failing (the "data" was noise level of EMC instrumentation). The customer did not know better and committed price and delivery on a big lot based on not having to make any changes. This one may end up in court. Luckily, this kind of error is rare, the 2-6 dB errors above are much more common. Recently I have rolled up a lot of this information in to a short web presentation I give to my clients so they can avoid these problems. Doug University of Oxford Tutor Department for Continuing Education Oxford, Oxfordshire, United Kingdom -------------------------------------------------------------- ___ _ Doug Smith \ / ) P.O. Box 60941 ========= Boulder City, NV 89006-0941 _ / \ / \ _ TEL/FAX: 702-570-6108/570-6013 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: d...@dsmith.org \ _ / ] \ _ / Web: http://www.dsmith.org -------------------------------------------------------------- On 12/17/14 4:01 PM, Carpentier Kristiaan wrote: I’m also glad to see that I’m not the only one.   Best regards Kris Carpentier,    From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: woensdag 17 december 2014 23:55 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   Indeed.  I’m glad to see that I’m not the only one seeing this.   Ghery S. Pettit   From: dward [mailto:dw...@pctestlab.com] Sent: Wednesday, December 17, 2014 2:50 PM To: Pettit, Ghery; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Brick power supplies and test errors (two topics)   Exactly.  While assessors may look over paperwork, that does not actually mean those involved in testing know what the standard to which they are testing actually says or if they do that they actually test to them.  Cannot tell you how many times I review reports from supposedly accredited labs and see that the test results make no sense or are just flat wrong. It is not just from one economic area either, it seems almost pandemic sometimes.    ​​​​​ Dennis Ward This communication and its attachements contain information from PCTEST Engineering Laboratory, Inc., and I sintended for the exclusive use of the recipient(s) named above.  It may contain information that is confidential and/or legally privileged.  Any unauthorized use that may compromise that confidentiality via distribution or disclosure is prohibited.  Please notify the sender immediately if you receive this communication in error, and delete it from your computer system.  Usage of PCTEST email addresses for non-business related activities is strictly prohibited.  No warranty is made that the e-mail or attachments(s) are free from computer virus or other defect.  Thank you.   From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: Wednesday, December 17, 2014 2:36 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   Yes, but the standards I’m thinking of are core to the computer industry.  CISPR 22, CISPR 32, CISPR 24, ANSI C63.4.  Really disturbing when you see key things that aren’t set up properly.  It makes you wonder what the qualifications are of the on-site assessors.  Paperwork is usually fine, the assessors understand ISO/IEC 17025.   Ghery S. Pettit   From: Ed Price [mailto:edpr...@cox.net] Sent: Wednesday, December 17, 2014 1:29 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   Ghery:   I found that business conditions have created large labs which strive to provide one-stop compliance services, and that this concept is subject to corruption by enthusiasm. By that, I mean that the labs often have a little subsection which is tasked with doing nothing but expanding the range of accreditations; these are the chaps who paper entire hallways with certificates of accreditation, allowing you to take comfort that if you ever needed a machine safety certificate for Kleptostan, you were already in the right place. A certain disconnect exists between these certificate harvesters (think marketing) and the other part of the lab (think engineering) which actually has to do that rare and idiosyncratic test.   Ed Price WB6WSN Chula Vista, CA USA   From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: Wednesday, December 17, 2014 10:00 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   I brought up some serious problems with accredited labs at the ASC C63 meetings in Mesa last month.  One accrediting body seems interested in dealing with the issue, the others not so much.  It’s so much fun to go into a lab that isn’t properly equipped to perform tests listed on its Scope of Accreditation.   Ghery S. Pettit   From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Wednesday, December 17, 2014 9:57 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   It would appear that the best efforts of lab accreditations are not living up to expectations? Or am I expecting too much?   Best Regards Charles Grasso Compliance Engineer Echostar Communications (w) 303-706-5467 (c) 303-204-2974 (t) 3032042...@vtext.com (e) charles.gra...@echostar.com (e2) chasgra...@gmail.com   From: Ed Price [mailto:edpr...@cox.net] Sent: Monday, December 15, 2014 4:01 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Brick power supplies and test errors (two topics)   Doug:   Did you create a write-up on what those errors specifically were, and how it happened that you noticed them in time to control them?   Ed Price WB6WSN Chula Vista, CA USA   From: Doug Smith [mailto:d...@emcesd.com] Sent: Sunday, December 14, 2014 3:49 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Brick power supplies and test errors (two topics)   Hi All, When I was at Auspex Systems (1996-2001) we had 8 EMC radiated emissions tests performed on our equipment (three 1500 lb cabinets full of disk drives). Of these, 4 tests had significant test errors, two major and two minor errors, but all had a large impact to our company! The tests were done at three different labs over time, all made at least one error. "Trust but verify." Doug - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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> - ---------------------------------------------------------------- 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>