Good People, Conflict of Interest Notice: my employer makes component SMPS.
The control loop for an analog load can also cause problems if the loop response time "beats" against a fundamental of the SMPS for that particular load setting. That is why my employer has a requirement to "sweep" the output load to detect any control instabilities. As for failure of the conducted emissions test, the end unit should be operated in a "normal" manner. That is, if the power supply has problems with conducted emissions in your box, then your box may need another power supply (and do not add "significant" capacitance to the output without consulting the SMPS mfr). luck, Brian > -----Original Message----- > From: [email protected] [mailto:[email protected]]On Behalf Of Ralph > McDiarmid > Sent: Thursday, May 18, 2006 8:24 AM > To: [email protected] > Subject: RE: Conducted emission measurements > > > We have discovered that some commercially available electronic loads > have conducted emissions of their own and these currents find > there way > into the device-under-test. > > Consider using either resistive load or an analogue controlled > transistor load bank. (no switching circuits or oscillators inside). > We built our own for all DVT testing including EMC. > > ====================================== > > Ralph McDiarmid, ASc > Compliance Engineering Group > Xantrex Technology Inc. > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of David > Gelfand > Sent: Thursday, May 18, 2006 8:09 AM > To: [email protected] > Subject: Conducted emission measurements > > We measured conducted emissions of a switched mode ac-dc power supply > and found that emissions are much higher when using an electronic load > compared to a resistive load. Can somebody explain why this is? > > Thanks, > > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
