This is where you can really use a mechanical engineer. If a board flexes and a ferrite does not, the resulting stress can fracture the ferrite. It is sometimes possible to add a board stiffener to to prevent or modify that kind of flexing. A high frequency swept sine-wave vibe test and a stroboscope might help identifiy board resonance and flexure points.
Cortland Richmond KA5S GE Aviation My opinions and NOT my employer's > [Original Message] > From: Moshe Valdman <[email protected]> > To: [email protected] <[email protected]> > Date: 6/29/2009 6:34:13 PM > 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]>
