For the record - I was doing a Single Fault analysis on a product that used a PTC and a relay to prevent welding switch contacts. (No it was not my idea - because...) when I got the engineer to simulate a s/c PSU the PTC exploded - sent burning material out through (compliant) ventilation slots onto the carpet which started to smolder.
The worst part of this story was yet to come when we discovered that the PTC have MODIFIED the di/dt of the fault current and destroyed discrimination between the thermal and electromechanical over-current devices up-stream. I cannot go into too much detail as it might reveal the name of the client - suffice it to say that the result could have been the biggest oil slick that the world has seen. That is why Product Safety engineering is so interesting. Best regards Gregg ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
