Sorry that I wasn't clear; I typically try to keep my questions general so not to get too detailed about the specific application. And thanks to Bob, Chris and Mike who have responded ... putting it into Chris's words ... I was just trying to find out if ferrites had ratings to prevent them from "j ust plain blowing the ferrite to smithereens". Also, I was looking for a shortcut if someone else had faced this question rather than reading through all of the vendor web sites.
I understand and have used ferrites quite often for typical EMI suppression; the ferrites typically being rated for the application currents, voltages, etc. In this case, the program is trying to protect a power supply input from the DO-160 waveform 5B pin injected lightning pulse of 300 volts open circuit & 300A short circuit. If the Gas Discharge Tube is located past (closer to the supply which was done for packaging limitations) than the "T" EMI filter, a question was raised as to whether the ferrite properties would be altered by the lightning pulse. Most of the standard literature on the use of ferrites does not address these types of transients. Susan Beard "Robert Wilson" <[email protected]>@majordomo.ieee.org on 06/04/2002 02:16:48 PM Please respond to "Robert Wilson" <[email protected]> Sent by: [email protected] To: <[email protected]>, <[email protected]> cc: Subject: RE: ferrite transient voltage/current response Your question is not all that clear. It appears to imply that transients have an affect on the ferrite beads, but it is the other way around (maybe that is what you meant). But in general, small ferrite beads have little effect, except at very high frequencies (hundreds of MHz), unless they are no longer "beads" (i.e. they are very large). Have a look at the various magnetics vendors data sheets and app notes. Magnetics Inc: www.mag-inc.com Fair-Rite Inc: www.fair-rite.com (whoever came up with THAT name should be shot! Steward Inc: www.steward.com Ferroxcube: www.ferroxcube.com Epcos (was Siemens): www.epcos.com Bob Wilson TIR Systems Ltd. Vancouver. -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: June 4, 2002 8:57 AM To: [email protected] Subject: ferrite transient voltage/current response Could someone point me to some good App Note information on the response of and affect on ferrite beads to transient voltage & current waveforms? The waveforms are based on the indirect lightning pulses specified in Section 22 of DO-160. Thanks in advance, Susan Beard ------------------------------------------- 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: [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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- 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: [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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- 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: [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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
