Doug, Have the NRTL call out the rated voltage of the fan only and that it is a Recognized component. Describing the min. CFM for a fan cooling a chip is not so important in this application. The CPU is mounted on a min. 94V-1 flame rated board and I asume an abnormal test by the NRTL was conducted with the fan disconnected with acceptable results.
In other applications such as equipment ventilation, calling out the min. CFM becomes important if you would like to use any Recognized Component fan manufacturer having a min. CFM equivalent to the fan mounted in the unit subjected to the tests. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 -----Original Message----- From: Doug McKean [mailto:[email protected]] Sent: Tuesday, June 19, 2001 11:19 PM To: EMC-PSTC Discussion Group Subject: You won't believe this ... Well, maybe you will. Dear all, In bringing a product through safety and having many issues, it might surprise you that after all was said and done, the entire safety approval reduced to a simple cfm rating fan for a chip both on the secondary side of the power supply. For some obvious reasons of which I hope you all understand, I can't provide too many details either here or off-line. Needless to say, the fan and chip companies have non-disclosure agreements them. In trying to obtain a simple cfm rating of the fan, a flurry of "call the other guy" began to happen. Nothing was resolved. Indeed, I went so far as to offer signing ANY type of non-disclosure agreements with both of them. But that was to no avail. And it remains so. So, the ECO gets cut to remove that part and mfr, plus any other parts by said mfr. An email gets sent to said fan company stating the resultant actions, etc, etc ... I doubt it will be of any concern to them. My reason for posting is that in the 20 or so years of doing EMC/Safety, I've never run into such a thing. Neither have I heard such a thing from associates who have been doing this work for as long or longer than I. This isn't an invitation to a bitch session about the companies. Nor is it a complaint about the NRTLs who are just doing their job. My experience in said matter with the NRTL has been great. I've run into something similar with patents and ink believe it or not. Mfr.'s are not really obligated to spell out exactly everything in something such as a patent, which I found surprising. What surprises me here is in the case of safety, where information is not disclosed. The NRTL didn't do cfm rating of the fan. In fact, there's really little no standard way to do cfm of fans. Thus, the reason why they allow similar fans within a mfr but not from another mfr. in some cases. So, I'm wondering some of the following: 1. Have any you ever run into something like this before? 2. If you have, what did you do about it? On and off line responses both welcome ... Regards, Doug McKean ------------------------------------------- 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," ------------------------------------------- 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,"
