Hi Doug:
I've always viewed the purpose of hipot testing as verification only. During engineering type testing, it is design verification. I disagree. The hi-pot test determines the minimum electric strength of the insulation system. Design is an indirect measure of electric strength by selecting the distances through solid and air (clearance) insulations. However, design rarely includes the shape of the electric field, which is a parameter that determines electric strength. Since hipot is so stressful to insulation… Again, I disagree. If the design is “good” (adequate electric strength), then the hi-pot test does not stress the insulation system. See Agilent Technologies Optocoupler Input-Output Endurance Voltage Application Note 1074. Best regards, Rich From: Doug Powell <doug...@gmail.com> Sent: Tuesday, August 14, 2018 1:50 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] X & Y Cap rating due to hipot test I've always viewed the purpose of hipot testing as verification only. During engineering type testing, it is design verification. During routine testing for manufacturing, it is workmanship and build verification. During type testing many safety standards will ask for hipot verification at various stages, after thermal/humidity tests, after abnormal operations, etc. Since hipot is so stressful to insulation, it is possible to introduce latent failures in the test sample after performing multiple hipot tests, combining many hipots into one is allowable by many inspectors. During routine testing, a brief hipot is added at the end of the manufacturing cycle to ensure wire routing is correct (spacings are maintained), integrity of insulation is maintained, in cases where vibration testing is involved a test for chafing of wire insulation and so on. Most safety standards have provision for "allowable disconnects" during the hipot such as surge suppressors and the like. Also, hipot of sub-assemblies in lieu of the finished assembly if it can be shown that the test is representative. Best to all, Doug -- Douglas E Powell doug...@gmail.com <mailto:doug...@gmail.com> http://www.linkedin.com/in/dougp01 - ---------------------------------------------------------------- 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>
