Hi all, Many thanks to all of you who participated in this ferrite discusson. I have leard a lot about ferrites the last 10 days.
In my special case, I would like to give you some information: We had a problem with conducted emisson on the DC supply line to a telecom product. The harmonic switching frequency was 160kHz and our problems was in the range 160kHz-5MHz. We used a toroid (DC cable five turns in the Toroid)and we managed to decrease the noise about 10-15dB in the frequency range 1-5MHz. The toroid had an outer/inner diameter of 61mm/36mm (a big one). We used a toroid with material 43 and its permeability is approximate 850. Material 43 has its application areas from 30-200MHz, so we should have had a toroid with an other material. I think a toroid with a material 77 (permeability 2000) could have helped us with the 160kHz-1MHz band. Next time ..... One last comment, try to avoid snap-on ferrites. Remember the air gap, you will have a large increase in the impedance even if you use strips to tighten it together. Use the solid ones .... See you later. Best regards Amund Westin, Oslo/Norway On 6 Mar 2001 19:16:37 -0000 [email protected] wrote: > >Hi all, > >During conducted emission test, we have 150kHz power supply switching >distrubance on the 48VDC-line, and we can not insert capacitors,chokes or any >filters on the line. > >Do you have any experience using ferrites to suppress noise in the band 100kHz - > 5MHz ? > >We have used ferrites with success on I/O-lines during radiated emission, but >no experience on DC-lines (use LISN). > >Best regards >Amund Westin, Oslo / Norway > >-- >Get your firstname@lastname email for FREE at http://Nameplanet.com/?su > >------------------------------------------- >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: > Michael Garretson: [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://www.rcic.com/ click on "Virtual Conference Hall," > > -- Get your firstname@lastname email for FREE at http://Nameplanet.com/?su ------------------------------------------- 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: Michael Garretson: [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://www.rcic.com/ click on "Virtual Conference Hall,"
