Moshe Unfortunately, I think your problem is shock rather than vibration. The instantaneous acceleration levels experienced in even apparently small shocks is much greater than during most vibration tests. If I understand you correctly, you have a loose ferrite clamped around a section of PCB. You could probably relieve the shock input by attaching the ferrite to the PCB with a resilient material such as silicone rubber. This should prevent the impacts that are probably imparting shocks in the 100's of g realm. I would prefer this to a more rigid material such as epoxy, because that may just transmit shock.
Best regards Neil R. Barker CEng MIET HonFSEE MIEEE Manager Central Quality e2v 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453571 Mob: (+44) 7801 723735 P Please consider the environment before printing this email. From: [email protected] [mailto:[email protected]] On Behalf Of Moshe Valdman Sent: 29 June 2009 17:34 To: '[email protected]' Subject: On board flat ferrites breaking Hi all, We have DC/DC supplies on boards which include flat ferrites mounted side to side (i.e. the PC conductors go through the ferrites) When we test the boards for NEBS, including 10 cm drop the ferrites tend to break (Interestingly during HALT or other vibrations the ferrites survuve well) Do you know this phenomenon? Is there some way to protect the ferrites? thanks in advance for your inputs, regards, Moshe - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ Sent by a member of the e2v group of companies. The parent company, e2v technologies plc, is registered in England and Wales. Company number; 04439718. Registered address; 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK. This email and any attachments are confidential and meant solely for the use of the intended recipient. If you are not the intended recipient and have received this email in error, please notify us immediately by replying to the sender and then deleting this copy and the reply from your system without further disclosing, copying, distributing or using the e-mail or any attachment. Thank you for your cooperation. ______________________________________________________ ________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
