| I am not entirely certain but one of the concerns is the ability of plastics to "cold flow". The temperature threshold is to determine at what point the magnitude of the migration is too much. This is the reason for measuring the 2mm diameter of the indentation at the ridge that is formed around the ball. A classic case is Teflon wire insulation. I don't know how many times a design engineer has told me they found this 1000V type EE wire (MIL-STD), only to learn that the UL rating is just 300V, if any at all. MIL-STD does not take into consideration cold flow as UL does. This is why UL style 1180 (equiv. Type EE) has a minimum wall thickness of 12 mils for 300V. UL style 1213 (Type E, 600V) has no voltage rating at all. Best, Doug Douglas E Powell https://www.linkedin.com/in/dougp01
I agree: I believe that is the reason for the test. I'm not sure that switch-mode wall warts can't get very hot under fault conditions. With best wishes DESIGN IT IN! OOO – Own Opinions Only www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England Sylvae in aeternum manent. From: Kunde, Brian [mailto:[email protected]] I assumed it had something to do with the old Wall Warts that was basically a transformer. In an overload condition, these transformers can reach temperatures exceeding 100ºC. You don’t want the plastic case to soften, warp, or open up and expose hazardous voltages, or worst. The Other Brian From: Carpentier Kristiaan [mailto:[email protected]] Hi group, Does any-one know the reason/background of the ball pressure test of thermoplastic parts (IEC60950-1, clause 4.5.5) and the chosen temperature of 125C. This test is performed - for example – on the plastic parts of a direct plug-in power supply as these parts “carry” the mains power supply pins. I can’t imagine a situation there that requires such a test and certainly not at 125C. Thanks for your feedback! Best regards Kris Carpentier - 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 <[email protected]> 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/ For help, send mail to the list administrators: For policy questions, send mail to: LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - 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 <[email protected]> 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/ For help, send mail to the list administrators: For policy questions, send mail to: ---------------------------------------------------------------- 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 <[email protected]> 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/ For help, send mail to the list administrators: For policy questions, send mail to: ---------------------------------------------------------------- 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 <[email protected]> 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/ For help, send mail to the list administrators: For policy questions, send mail to: | ||
- [PSES] Ball pressure test of thermoplastic parts Carpentier Kristiaan
- Re: [PSES] Ball pressure test of thermoplastic p... Kunde, Brian
- Re: [PSES] Ball pressure test of thermoplast... John Woodgate
- Re: [PSES] Ball pressure test of thermop... Doug Powell
- Re: [PSES] Ball pressure test of thermoplastic p... Covell, Richard
- Re: [PSES] Ball pressure test of thermoplast... John Allen
- Re: [PSES] Ball pressure test of thermop... Carpentier Kristiaan
- Re: [PSES] Ball pressure test of thermoplastic p... Peter Tarver
- Re: [PSES] Ball pressure test of thermoplast... John Woodgate
