Hi Doug: I am alarmed that you experienced breakdowns by an 800-volt pulse when the dielectric strength of the primary circuits is at least 1500 volts rms. I have a few questions:
1. What was the 800-volt waveform? You applied the pulse common mode, which I assume is to both line and neutral conductors connected together and to the ground wire. (This is the hi-pot test configuration.) Please confirm. 2. How did you detect breakdowns, especially in the next microseconds after applying the pulse? 3. Small wall-warts are typically two-wire with no ground. (The hi-pot test is to foil wrapped around the enclosure and to the secondary.) What was your test configuration? 4. Primary-to-ground and primary-to-secondary in a typical product consists of Y capacitors, solid insulation, and air insulation. Since the air insulation is 2 mm or more, this is unlikely the site of the breakdown. Solid insulation should easily withstand 800 volts (more likely 8,000 volts). So, this leaves the Y capacitors as likely suspects. What is your guess as to the EUT component that exhibits this phenomenon? 5. Were any of the units you tested malfunctional or permanently damaged due to your tests? 6. How can we get a copy of your paper? Thanks, 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
