Concur about below vendors and Ed's comments. Need to look at the power supply installation instructions and Conditions of Acceptability. Wrote some install instructions for a model series stating that output is floated, so grounding of output not recommended unless noise currents returned to/using blah blah blah. Every last customer complaint of emissions issues was where the output return was randomly strapped to their chassis, which was randomly strapped to the ground bond wire.
Also should be noted that component power supplies vendors cannot really say anything about radiated emissions. Too dependent on the end-use construction. At best, you can infer radiated performance from the reported conducted emissions. Brian From: S Drysdale [mailto:[email protected]] Sent: Thursday, February 25, 2016 6:58 AM To: [email protected] Subject: Re: [PSES] Recommendations for DC-DC converter Hi Ed, I believe you hit the nail on the head, figuratively. The problem is the use of a commercial DC-DC converter that is not meeting the required specification. The product and components must fit in a tight space, and spacing is extremely tight, so there is limitations on the external components we can add to filter this. This is the main problem we are running into with the current DC-DC converter, and I think a different DC-DC converter may require substantially less external filtering, or hopefully none at all. I have found gaia and vicor power imply some degree MIL-STD compliance, but I was hoping for manufacturer or product recommendations from those familiar with the concern. Best Regards, Scott Drysdale, OOO - Own Opinions Only http://ca.linkedin.com/in/scottdrysdale On Wed, Feb 24, 2016 at 4:22 PM, Ed Price <[email protected]> wrote: Scott: First, can we assume that the converter itself has already been successfully tested to RE102? If you are trying to use a commercial converter in a MIL environment, you may be starting at a big disadvantage. Some converter vendors offer an auxiliary active filter module, so get the vendor involved in your problem. The RE problem is probably not originating from radiation directly from the converter case, but from radiation from cabling connected to the converter. You may be able to decrease common mode currents with external ferrites or inductance, twisted pair power feeds may help and you should carefully review the mounting of the converter to the platform frame. Ed Price WB6WSN Chula Vista, CA USA From: S Drysdale [mailto:[email protected]] Sent: Wednesday, February 24, 2016 11:41 AM To: [email protected] Subject: [PSES] Recommendations for DC-DC converter All, My client has a very tight imposed limit for radiated emissions. Let's assume MIL-STD RE102 army ground. We are exceeding emissions caused by the DC-DC converter. Shielding is difficult in this application, and something we would like to avoid. Space requirements are an issue, and we think it may be easier to switch the module altogether. Input 48Vdc, Output is 12Vdc, 1.7A (or ~20W). Size is somewhat important, where smaller is better, but meeting this radiated emission limit is essential. Any recommendations? Best Regards, Scott Drysdale https://www.linkedin.com/in/scottdrysdale OOO - Own Opinions Only - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
