RE: Medical Grade Transformers
From: jeff collins Sent: Friday, July 13, 2007 5:00 PM Can anyone recommend a Transformer manufacturer that makes custom medical grade transformers? Speaking of on-line databases, try searching on UL's category named Transformers, Construction Only - Component (XORU2). Add a keyword for a standard number (e.g. 60601, 2601, 544). Construction only transformers meet the insulation requirements (within the limitations identified in the reports) of the identified standard(s) and the product category is designed to allow for custom builds, but will still need thorough testing in the end-product. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
RE: Medical Grade Transformers
List Members, Can anyone recommend a Transformer manufacturer that makes custom medical grade transformers? We will obviously need to get this component Approved/Listed/Certified and want to work with a vendor that is established and reputable in handling agency listings and manufacturing requirements. Thanks in advance, Jeff Collins - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: medical-grade transformers
Hi Ged: 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 ? Thin insulation is presumed to be subject to pin-holes. If 1 layer of insulation, then the insulation must be thick rather than thin, hence 1 mm thickness. We presume no pin-holes in thick insulation, and the insulation comprises reinforced insulation. If 2 layers of thin insulation, then presume a pin-hole in one layer, and that the pin-hole will not overlay a pin-hole in the other layer. If that pin-hole is 0.15 mm, then we know that the air in that pin-hole will at least withstand the mains voltage. Therefore, the construction still has two insulations in series, one being the 0.15 mm air of the pin-hole, the other being the 0.15 mm thick solid insulation. The 2 insulations in series comprise double insulation. If 3 layers of thin insulation, then presume a pin-hole in one layer, and that the pin-hole will not ovelay a pin-hole in the adjacent layer. The remaining 2 layers comprise double insulation. (In IEC 60960, the requirement for 1 layer in a 2-layer system is 0.4 mm thickness.) Best regards, Rich ps: I'm not certain of my explanation for 2 layers. This rationale came from 60950, and I have applied it to 60601. --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
Re: medical-grade transformers
Regarding my query on medical equipment transformer construction (EN-60601-1, clause 57.9.4(e)), can I be a bit more specific. - How were insulation thickness requirements decided, and why is the thickness requirement lower if insulation is 2-layer rather than single-layer ?. - Why are single-layer and 2-layer insulation requirements defined in terms of thickness, yet 3-layer insulaton requirements defined in terms of dielectric strength ?. Thanks Ged Dean ** 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
RE: medical-grade transformers
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 ndev...@entela.com e-mail Entela, Inc. A Certified Woman Owned Business www.entela.com -Original Message- From: Dean Gerard (gdean) [mailto:gd...@ncht.trent.nhs.uk] Sent: Monday, July 29, 2002 9:29 AM To: 'emc-p...@majordomo.ieee.org' 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
