Hi Doug:
My comments are imbedded in your message. Best wishes for the New Year! Rich From: Doug Powell [mailto:doug...@gmail.com] Sent: Friday, January 06, 2017 6:32 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Thermal equilibrium - 10% rule I agree that thermal equilibrium can never be achieved especially in light of the zeroth law of thermodynamics, but also for more reasons than the exponential nature of the thing. Possibly a better phrase to use is thermal stability. Agree! I actually believe that the standards committees will re-use the text of previous standards and averse to changing it in subsequent revisions with the rationale that it worked in the past Agree! and possibly there's someone relying on this bit of information. The 10 percent of the previously elapsed time business simply does not make sense to me and I have never used it in actual testing. Nevertheless, it has shown up in a couple of recently published standards I use for large format storage batteries. In my case, I have an outdoor product that weighs in at more than 100,000 pounds and thermal equilibrium cannot be achieved in 24 hours, meanwhile the daily cyclical temperature compound the problem of measurement. Obviously, I am going to have to do live compensation of ambient conditions during the test and not afterward. Put a tent over it, and put a heater in the tent to simulate the hottest day. Take your temperature measurements just before the outdoor temperature causes the tent and equipment to decrease in temperature. Thanks all, Doug - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
