Brian,
Also look carefully at the notes in Table 2B and 2C. A PTC has to act within 5s. The current ratings of over current protective devices are based on fuses and circuit-breakers that break the circuit within 120 s with a current equal to 210 % of the current rating specified in the table. Other devices have to essentially meet or beat the graphs for a IEC 60127-2, Sheet 3 fuse. Jim Goedderz Tyco Safety Products/Sensormatic Sr. Principal Engineer Product Safety Engineer 561 912-6378 561 912-6084 FAX [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Kunde, Brian Sent: Wednesday, November 18, 2009 11:37 AM To: [email protected] Subject: PTC Test Requirements According to IEC/EN 60950 section 2.5b, a positive temperature coefficient device (PTC) can be used to limit current for a limited power source circuit. It says the PTC has to “pass the test specified in IEC 60730-1, clauses 15, 17, J.15 and J.17”. I don’t have this standard. Can someone outline the test requirements for me? I’m trying to avoid adding another standard to our library unless we really need to. Application: Sometimes we would like to supply 24Vdc to an I/O port to operate a device outside the fire enclosure. I assume a PTC or Pico Fuse can be used for this application. We drive the I/O circuit with a programmable High-Side Driver programmed to 4 amps max but someone suggested that we cannot rely on it for safety in this application. Any other suggestions? Thanks to all, The Other Brian _________________________ 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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]> - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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]>
