I may have missed something, but my understanding of clamp injection is that it is a transformer in series with the cable-under-test (CUT). That being so, the CUT has loads at either end. Even if the AE side is an open circuit, the EUT side could be a dead short and draw a lot of current. Further I will confess to not understanding the rationale for raising the impedance on the AE side (if the CUT is unshielded). If the AE end is a high impedance relative to the EUT end, then the injected rf potential will be dropped across the AE end, instead of the EUT end, which is where I would think the injected potential should end up. What obvious point am I missing?
> From: <[email protected]> > Reply-To: <[email protected]> > Date: Fri, 23 Jan 2004 19:45:35 +0200 > To: <[email protected]> > Subject: RE: Clamp Injection EN61000-4-3 Question > > > Well, > if you can maintain the 150 ohm to AE, your current cannot exceed Uo/150, > right? > > >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]]On Behalf Of ext >> [email protected] >> Sent: 23 January, 2004 19:08 >> To: [email protected] >> Subject: RE: Clamp Injection EN61000-4-3 Question >> >> >> >> My product is a relatively large, 19"-rack mounted device. >> And I made a (kind of obvious) mistake, it is -6 (conducted >> immunity) and not -3. >> >> The chassis is supposed to be bonded to Safety Ground. >> 6.2.2.1 provides requirement to connect the EUT chassis to >> ground reference plane through CDN-M1 (to increase the CM impedance). >> >> 150 Ohm (plus/minus tolerancefrom chassis to GND is a moot >> point at the higher end of the tested frequency range, due to >> the impedance of the chassis and the attached cables vs. >> environment, that is in parallel to the CDN. >> >> Let me rephrase my original question: >> >> Am I allowed to measure current and stop the test if the >> current into EUT exceeds Uo/150, even if I can meet the >> formas requirements on the EUT and AE setup/impedances? >> >> Thanks, Neven >>> >>> You're right, not always (i.e. with safety class II). >>> But if there's earth terminal a M-1 is connected to it, see 6.2.1.1 >>> of 2nd Ed. >>> Ari >>> >>>> -----Original Message----- >>>> From: [email protected] >>>> [mailto:[email protected]]On Behalf Of >> ext Oliver Betz >>>> Sent: 23 January, 2004 11:49 >>>> To: [email protected] >>>> Subject: RE: Clamp Injection EN61000-4-3 Question >>>> >>>> >>>> >>>> <[email protected]> wrote: >>>> >>>> [EN61000-4-6] >>>> >>>>> Some comments to Neven: >>>>> -When you use BCI clamp you can measure and limit the >>>> current as you describe. >>>>> -The impedance is not >150 ohms but with +/- tolerance, >> see Table 3. >>>>> -The EUT needs to have 150 ohms from chassis to earth so >>>> the impedance is not as low as you say >>>> >>>> Really "_chassis_ to earth" - where do you read this? >>>> >>>> Oliver >>>> -- >>>> Oliver Betz, Muenchen >>>> >>>> >>>> ------------------------------------------- >>>> 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 >> >> >> ------------------------------------------- >> 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 > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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