I have two questions for the list today. First, product is ITE tested to EN 60950. Primary power (115 VAC) is fed to a printed circuit board. I know there are creepage and clearance requirements for the etches carrying AC that run on the surface of the board, or on any layer for that matter. That is there are spacings required between AC etches and other etches whether signal or ground or whatever. What I cannot recall is if creepage and clearance applies to etches on different layers. Say AC on etch on surface and signal on etch on first inner layer. Assume standard multilayer board with typical thicknesses. Don't recall 60950 saying anything about that and don't have a copy of the standard to review. Does creepage and clearance apply to this situation? Does the high insulation value of the FR-4 play any part in reducing the requirements?
Second question is about a linear power supply with a very large toroid transformer (600+ VA) and two very large (call them garbage can sized) caps. This power supply fails Harmonics when tested to EN 61000-3-2; it is almost double the limit for harmonics currents. Short of going to a switcher, are there any solutions that are not extreme to make the supply pass the test? As always, looking forward to the diverse suggestion I am sure to read. And thanks for your input. Scott Douglas This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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://www.ieeecommunities.org/emc-pstc
