Scott, It looks like I agree with you, but I'm just trying to see if I can get filter vendors to publish critical data about their parts. As we say in England ( and possibly elsewhere too ), " It's like flogging a dead horse "
Best regards, Derek. "Lacey,Scott" wrote: > Derek, > We stock a 16 amp line filter which we have used on lower current products > specifically to prevent saturation of the choke when used as a protective > device for external events such as EFT. I put one on a product containing an > "industrial" computer supplied by a business partner to solve a problem with > Ethernet communications during EFT testing. Interestingly, although the > computer was CE marked, EN61000-4-4 was absent from the list on the > compliance label. I had a tough time convincing the engineering manager that > the larger device was needed. He wanted to use a smaller filter that replace > the IEC cord inlet. > > The answer to your question is that, in the absence of reliable data from > the vendors, you must either devise a quick test or deal directly with a > good custom magnetics house that will build a part to your specs. > Unfortunately, today we often find ourselves dealing with "puppies" after > the "old dog" engineers have either retired or been laid off. A lot of these > kids don't know, don't care, and think truthfulness is an impediment to > sales. It can be difficult tell stupidity from malice as they both cause > similar problems. > > Scott Lacey > > -----Original Message----- > From: Derek Walton [SMTP:[email protected]] > Sent: Thursday, December 02, 1999 2:47 PM > To: IEEE EMC Discussion Group > Subject: Common Mode Choke > > Good day all, > > I'm refining the input filter of a 150 watt SMPS. Nothing flashy, > just a > few caps and a common mode choke. > > The current is drawn by the supply in short bursts as the DC link > cap is > charged. I've shown that peak current reaches 6 amps for up to 2 ms. > I've also demonstrated that the CM choke, while rated for the RMS > current ( a 2 amp device ), does saturate when the current exceeds > about > 4 amps. > > I've been trying to find out from the vendors, what current it takes > to > saturate the CM choke. I've had answers from CM chokes can't > saturate to > "that's not an important parameter, use the rms figure".... > > My question is, with over 20 potential vendors of this type of > component, is there any way I can find out saturation performance > without buying one of each type and testing it. I've played with 3 > so > far, the most expensive was NOT the best! I guess, I'm curious why > more > folks don't know about this effect also..... > > Thanks, > > Derek Walton > Owner > L. F. Research EMC Design and Test Facility > 12790 Route 76, > Poplar Grove, > IL 61065. > www.lfresearch.com > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). > -- Derek Walton Owner L. F. Research EMC Design and Test Facility 12790 Route 76, Poplar Grove, IL 61065. www.lfresearch.com --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
