Ron, 1. Double insulation = basic insulation + supplementary insulation.
2. I assume that you are familiar with the medical requirements and that other than dielectric strength, there are additional requirements for insulation, like clearance, creepage and distances through insulation. 3. You may use this ac/dc convertor as basic insulation (1500 Vrms) or as supplementary insulation (2500 Vrms) between the primary and secondary circuits. 4. If ac/dc convertor is treated as basic insulation (1500 Vrms) then you must add an supplementary insulation (2500 Vrms) between the convertor secondary circuits and the applied part. If the applied part is polymeric, this is easily achieved by the dielectric properties of the insulating material used to fabricate the part. Otherwise, you can use components such as adding min. 2500 Vrms optocouplers or a/d convertors between the secondary circuits of the ac/dc convertor and the applied part. 5. If ac/dc convertor is treated as supplementary insulation (2500 Vrms), then you must add basic insulation (1500 Vrms) between the convertor secondary circuits and the applied part. If the applied part is polymeric, this is easily achieved by the dielectric properties of the insulating material used to fabricate the part. Otherwise, you can use components such as adding min. 1500 Vrms optocouplers or a/d convertors between the secondary circuits of the ac/dc convertor and the applied part. 6. It is true that the electric strength voltages in the 601 standards are rms values. However, I do not see why you cannot apply dc values - ie take the rms value and multiple by 1.414. This is allowwed in many standards like the 950 series for ITE and the 1010 series for laboratory, measurement and control. Hope the above helps in the design of your medical product. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 -----Original Message----- From: Ron [mailto:[email protected]] Sent: Wednesday, August 29, 2001 5:26 PM To: EMC Subject: Medical application-Isolation voltage I have a medical application that requires "double insulation" from the Mains to an "applied part" according to IEC60601. IEC60601 states that for a reference voltage of 250v and double insulation, the test voltage is 4000v for 1 min. I am assuming that the voltages are RMS values. How does one go about meeting the 4000v test when the highest rated ac-dc converter I can find is 3500v RMS continuous. Any help is appreciated. Thanks. Ronald Cyprowski Vascor Inc. 566 Alpha Drive Pittsburgh PA 15238 412-963-7438 x139 [email protected] ------------------------------------------- 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: Michael Garretson: [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: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- 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: Michael Garretson: [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: No longer online until our new server is brought online and the old messages are imported into the new server.
