Hi Brian:
> There are two parameters here - the max continuous rated rms voltage which is normal operations, and the 'clamping' voltage where the component goes low impedance which is abnormal operations. We are talking about the former; and the latter is not necessarily part of any safety requirement - other than the component shall not puke it guts out during an abnormal operating condition. > Just for clarification... a VDR has TWO "normal" operating modes. At any voltage below the clamping voltage, the resistance is high. At any voltage above the clamping voltage, the resistance is low. Transient overvoltages are normal, not abnormal. This is why we must address both operating and transient voltages in product design. For example, electric strength is a parameter that is based on the transient voltage. I believe thinking of a transient voltage as normal helps in the design of equipment, and especially when a safety engineer must interact with an equipment design engineer. Best regards, Rich - 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]>
