RE: Components to suppress fast transient / bursts
I suggest you apply self-induction with low parallel capacity such as ferrites before any clamping device. Standard varistors do perform self induction in series with the clamping part. The source impedance of the EFT pulse is 50 Ohm. If your low impedance path to ground is 1 Ohm inductive still 40 volts reside. I can assure you that 1 Ohm to ground sereis impedance at this frequency is NOT an easy target. So first increase the impedance of the EFT pulse as high as physically possible (200-300 Ohms) in the incoming cable/wire and then lead to ground using a low inductace capacitor and varistor. If no impedance is possible use faster devices such as transil (semiconductor) preferably in SMD version to reduce series impedance. Possibly your equipment don't need that much decoupling; just give it a try. uP equipment may be very hard to decouple. Note that relay's and optocouplers are virtually transparent to this pulse... Potential free relay contact outputs are often overlooked. I decoupled thyristor lamp solid state relays using ferrites last year. I needed 4 big ones in series to stop the thyristor from igniting. Need I mention that varistors could not be applied here ? Regards, Gert Gremmen, (Ing) ce-test, qualified testing === Web presence http://www.cetest.nl CE-shop http://www.cetest.nl/ce_shop.htm /-/ Compliance testing is our core business /-/ === >>-Original Message- >>From: owner-emc-p...@majordomo.ieee.org >>[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of >>am...@westin-emission.no >>Sent: Wednesday, December 12, 2001 9:51 PM >>To: emc-p...@majordomo.ieee.org >>Subject: Components to suppress fast transient / bursts >> >> >> >>Hi all, >> >>I do not have any experience with components which could suppress a 2kV >>(5ns/50ns) electrical fast transient (Burst). >> >>Anybody in the group who could come up with some suggestions ? >> >>Best regards >>Amund Westin,Oslo/Norway >> >> >> >>--- >>This message is from the IEEE EMC Society Product Safety >>Technical Committee emc-pstc discussion list. >> >>Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ >> >>To cancel your subscription, send mail to: >> majord...@ieee.org >>with the single line: >> unsubscribe emc-pstc >> >>For help, send mail to the list administrators: >> Michael Garretson:pstc_ad...@garretson.org >> Dave Healddavehe...@mediaone.net >> >>For policy questions, send mail to: >> Richard Nute: ri...@ieee.org >> Jim Bacher: j.bac...@ieee.org >> >>All emc-pstc postings are archived and searchable on the web at: >>No longer online until our new server is brought online and >>the old messages are imported into the new server. >> >><>
Re: Components to suppress fast transient / bursts
I've had good results using ferrite cores. They help radiated emissions as well. P.S.: I was surprised to see your location. I'll be coming to your city for the first time on Saturday. This visit caused me to ask the question concerning snow on OATS sites. On Wed, 12 Dec 2001 21:50:35 +0100, wrote: >I do not have any experience with components which could suppress a 2kV >(5ns/50ns) electrical fast transient (Burst). > >Anybody in the group who could come up with some suggestions ? > >Best regards >Amund Westin,Oslo/Norway --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Components to suppress fast transient / bursts
Hi Amund, A properly sized varistor ( sometimes with capacitor in parallel) is quite effective. You will find IEC 1000-4-4 mentioned in some varistor datasheets. Just mind that you have the energy rating correctly specified and for really high speed response, opt for surface mount. The varistors have a parameter called the clamping voltage and you need to be careful that all your protected front end is rated to at least that voltage. Varistor sources include ( I think) EPCOS, Keko-Varicon, Murata, Littelfuse, TDK components, Panasonic etc. You can opt for tranzorbs from the likes of General Semi (Vishay), ST Microelectronics etc for tighter clamping voltages but these are semiconductor types and tend to 'break' when subjected to high energy transients like the surge (EN 610004-5) or automotive load dumps (ISO 7637-1, 2 Test pulse 5). Regards - Chris -Original Message- From: am...@westin-emission.no [SMTP:am...@westin-emission.no] Sent: Wednesday, December 12, 2001 8:51 PM To: emc-p...@majordomo.ieee.org Subject:Components to suppress fast transient / bursts Hi all, I do not have any experience with components which could suppress a 2kV (5ns/50ns) electrical fast transient (Burst). Anybody in the group who could come up with some suggestions ? Best regards Amund Westin,Oslo/Norway --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Components to suppress fast transient / bursts
Hi all, I do not have any experience with components which could suppress a 2kV (5ns/50ns) electrical fast transient (Burst). Anybody in the group who could come up with some suggestions ? Best regards Amund Westin,Oslo/Norway --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
