Resent to EMC-PSTC without the jpeg of my signature which got it rejected last time!
From: John Allen [mailto:[email protected]] Sent: 29 January 2013 12:17 To: '[email protected]' Cc: '[email protected]'; 'Allen, John (GE Oil & Gas, Non-GE)'; '[email protected]' Subject: FW: Test Voltages for secondary circuit creepage distances IEC/EN 61010:2010 section 6.7.3 Ray You kindly helped me a few months ago on the changes between Ed 2 & Ed 3 of the standard, and we have been getting into it in quite a lot of detail in my new contract job - but we have run up against a specific issue which is puzzling us a lot, as raised below by my colleague Peter Phillips. Having read that email, I would also like to add that the voltage multiplication factor for the clearance distance hipot test increases dramatically at the low end of the working voltage ranges of Table 7 - to the extent of it being around 50x times the working voltage. I realise that at very small clearance distances the subject of ionization becomes an issue, but, even so, these multiplication factors do seem very high. So please can you explain why they are so high and why the test appears to always an AC test with no DC option? Thanks in advance John Allen Compliance Engineer Sensor & Electronics GE Oil & Gas T +44 1252 862200 (switch) [email protected] (But sent from my personal email a/c!) Sondex Wireline Engineering Department X107 Range Road, Cody Technology Park Farnborough, Hants, GU14 0FG, UK From: Phillips, Peter (GE Oil & Gas, Non-GE) Sent: 29 January 2013 11:19 To: '[email protected]' Subject: Test Voltages for creepage distance BS EN 61010:2010 section 6.7.3 Hi Can you clarify what voltage I should test to for Creepage distances on a special design of coaxial connector in a Overvoltage Category II secondary circuit? >From the connector drawing I have determined a min Creepage distance of 1.375 mm. Interpolating from IEC/ EN 61010:2010 section 6.7.3 Table 6 for pollution degree 2 and material group III, this gives a maximum working voltage of 93.75 V ac rms. However, unlike Table 7 for the clearance distances, there is no test voltage specified for this Creepage distance. The question is: should I use the Creepage working voltage I have obtained and insert it into column 1 ( ac secondary working voltage) of Table 7 to obtain a test voltage? For a mains supply >150 <= 300V ac rms this would give a test voltage of 895V ac rms. Then if I apply to this the altitude correction of table 7 for, section 6.8.1 for 0 altitude I get a test voltage figure of 1038V ac rms. This seems a bit high so I wonder if I am making a wrong assumption. Best Regards Peter Phillips - ---------------------------------------------------------------- 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/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
