Hi, >From Appendix A, General Guidance and Rationale, for Clause 57.9
"...For reasons of PATIENT safety additional requirements must be applied to the construction of such transformers, e.g. restriction of LEAKAGE CURRENTS flowing to PATIENT CIRCUITS." 57.9.4 e) In transformers with REINFORCED INSULATION or DOUBLE INSULATION the insulation between the primary and secondary winding shall consist of: - one insulation layer having a thickness of at least 1 mm, or - at least two insulation layers with a total thickness of not less than 0.3 mm, or - three layers provided that each combination of two layers can withstand the dielectric strength test for REINFORCED INSULATION. Ned Devine Program Manager Entela, Inc. 3033 Madison Ave. SE Grand Rapids, MI 49548 1 616 248 9671 Phone 1 616 574 9752 Fax [email protected] e-mail Entela, Inc. A Certified Woman Owned Business www.entela.com -----Original Message----- From: Dean Gerard (gdean) [mailto:[email protected]] Sent: Monday, July 29, 2002 9:29 AM To: '[email protected]' Subject: medical-grade transformers With regard to transformer construction, CLAUSE-57.9.4(e) of EN-60601-1 General Requirements for Safety of Medical Electrical Equipment requires:- "In transformers with REINFORCED INSULATION or DOUBLE INSULATION the insulation between 1ary and 2ary windings shalll consist of - - 1 insulation layer having thickness at least 1mm, or - at least 2 insulation layers with total thickness not less than 0.3mm, or - 3 layers provided each combination of 2 layers can withstand the dielectric strenght test for REINFORCED INSULATION" Can anyone explain ther rationale behind these requirements ? Thanks. Ged Dean Nottingham City Hospital. ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. NCHT ********************************************************************** ------------------------------------------- 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" ------------------------------------------- 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"
