Hi Pat, There seem to be large time lags on my responses propagating through the list server. It seems that you have two possible issues:
1. If different runs of the test reveal failures to the limit line; then you should investigate why those failures happen. However, as John pointed out there are NO repeatability requirement for your switch-mode power supply (EUT) ---- some one is interpreting the standard incorrectly. 2. If different runs of the test reveal different profiles that all comply with the limit line then you have passed and you are finished (even if these runs differ from each other by greater than 5%). Hope this helps. Kurt From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Wednesday, April 21, 2004 5:35 AM To: [email protected] Subject: Re: EN61000-3-2 repeatability test In response to Kurt's question "It seems that the solution path is to determine why the EUT generates different LF emissions profiles ..." The EUT is a switching power supply, and like all electronics equipment, the components are packed close together. This includes the PFC control circuitry, the PFC boost inductor, and the power transformer. Considering the PFC circuitry has control signals in the tens of microamperes, and it operates in a noisy signal environment of fast switching magnetic fields, it's not had to imagine the measurements varying because of local interference ('jitter' in the digital world). If we had realized this type of 'repeatability' test was to be applied when we designed the product, it would have been taken into account. We thought the PFC design was successful when the emissions were far below the limit line. --- Pat Lawler [email protected] On Tue, 20 Apr 2004 07:42:38 -0700, "Kurt Fischer" <[email protected]> wrote: >I do not have a copy of the standard so I am relying on memory: > >1. The 5% repeatability requirement stated in the standard refers to >Instrumentation repeatability and validation (as Ken referred to in his >email). > >2. The problem stated in Pat's email is that the EUT has different >measurement results when measured at different times. > >It seems that the solution path is to determine why the EUT generates >different LF emissions profiles and determine if these profiles meet the >limits in a reasonable number of cases or trials per the standard. To the >best of my memory, there is no requirement that the repeatability >measurements of the EUT itself be +/- 5%. > >Regards, >Kurt Fischer > >-----Original Message----- >From: Hall, Ken [mailto:[email protected]] >Sent: Tuesday, April 20, 2004 5:53 AM >To: Kurt Fischer; Pat Lawler; [email protected] >Subject: RE: EN61000-3-2 repeatability test > > >Hello, > >We just purchased the York HFG01for Site reproducibility/RoundRobin testing >and use the HPET ( the for cyclic checks. The HP59510A switch box is >replaced by a solid state relay the load resistors are glowcoils. > >Regards, >Ken Hall > _____ > >From: [email protected] on behalf of Kurt Fischer >Sent: Mon 4/19/2004 7:42 PM >To: 'Pat Lawler'; [email protected] >Subject: RE: EN61000-3-2 repeatability test > >You should use the same EUT (which must be stable and repeatable). If you >are obtaining drastically different results then you do not know if it is >the EUT or the test setup/instrumentation that is effecting the results. > >I would suggest using something like an incandescent light bulb to run the >test and check the repeatability of the instrumentation and test setup. > >Just my 2 cents. > >Good Luck, > >Kurt > >-----Original Message----- >From: [email protected] >[ mailto:[email protected] ><mailto:[email protected]> ]On Behalf Of Pat Lawler >Sent: Monday, April 19, 2004 5:36 PM >To: [email protected] >Subject: EN61000-3-2 repeatability test > > >When the 'Repeatability' clause in EN61000-3-2:2000 (clause 6.3.2.1) is >applied, is the comparison value (reference value) the result from another >test run, or is it the test limit? > >For example, the harmonic test limit is 300mA, and the values from two test >runs are 7.4mA and 13mA. > >1) If the comparision value is from the other test run: >13mA-7.49mA >-----------*100=42.4% (failing the test) > 13mA > >2) If the comparison value is the test limit: >13mA-7.49mA >-----------*100=1.8% (passing the test) > 300mA > >Method 1 seems overly stringent, but I can't find anything in the standard >covering the method. Is this detail covered in another standard (like >61000-4-7?) >--- >Pat Lawler >pat dot lawler at verizon dot net > > >------------------------------------------- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ieee-pses.org/ ><http://www.ieee-pses.org/> > >To cancel your subscription, send mail to: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc ><http://www.ieeecommunities.org/emc-pstc> > > >------------------------------------------- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ieee-pses.org/ ><http://www.ieee-pses.org/> > >To cancel your subscription, send mail to: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc ><http://www.ieeecommunities.org/emc-pstc> > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
