RE: 48/60 Vdc Centralized Office Equipment
Joe - The 72Vdc issue was an attempt to explain the TNV-2 aspect, since that clearly exceeds SELV limits. The influences of polarity is intended to address miswiring and tends to force some type of reverse polarity protection (diodes, connectorization or something more sophisticated). CO battery plant tolerances are generally not adequately addressed in IEC60950, but an attempt to address the issue is in the third dashed paragraph of Subclause NAB.2 of CSA/UL60950, 3rd ed. These values are largely derived from ANSI T1.315. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com -Original Message- From: Joe Finlayson Peter, I am aware of the float voltages and agree that a 60VDC rating **should be** tested up to 72VDC. However, I still feel that DC tolerances are not adequately reflected in the body of the standard. Is the phrase influences of polarity intended to reference float voltages??? Thx, Joe -Original Message- From: Peter L. Tarver Joe - When the nominal CO supply voltage is 60Vdc and batteries are charging, the float voltage is closer to 72Vdc. Test houses are aware of this and take it into account when performing their evaluations. Regards, Peter L. Tarver, PE -Original Message- From: Joe Finlayson I see section 1.4.5 addressing the determination of the most unfavorable supply voltage for a test. The tolerance to be taken into account is clear for the determination of AC mains powered equipment. All it says for DC powered equipment is that the influence of polarity shall be taken into account. I see coming up with a potential of 60VDC either way. Was the intent here to state something I am missing? Thx, Joe --- 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: 48/60 Vdc Centralized Office Equipment
Peter, I am aware of the float voltages and agree that a 60VDC rating **should be** tested up to 72VDC. However, I still feel that DC tolerances are not adequately reflected in the body of the standard. Is the phrase influences of polarity intended to reference float voltages??? Thx, Joe -Original Message- From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: Monday, October 21, 2002 10:30 AM To: Joe Finlayson; EMC-PSTC (E-mail) Subject: RE: 48/60 Vdc Centralized Office Equipment Joe - When the nominal CO supply voltage is 60Vdc and batteries are charging, the float voltage is closer to 72Vdc. Test houses are aware of this and take it into account when performing their evaluations. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services 2000 Ringwood Ave. San Jose, CA 95131-1749 V: 408-904-2081 F: 408-904-2095 M: 408-234-3529 peter.tar...@sanmina-sci.com -Original Message- From: Joe Finlayson I see section 1.4.5 addressing the determination of the most unfavorable supply voltage for a test. The tolerance to be taken into account is clear for the determination of AC mains powered equipment. All it says for DC powered equipment is that the influence of polarity shall be taken into account. I see coming up with a potential of 60VDC either way. Was the intent here to state something I am missing? Thx, Joe --- 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: 48/60 Vdc Centralized Office Equipment
Joe - When the nominal CO supply voltage is 60Vdc and batteries are charging, the float voltage is closer to 72Vdc. Test houses are aware of this and take it into account when performing their evaluations. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services 2000 Ringwood Ave. San Jose, CA 95131-1749 V: 408-904-2081 F: 408-904-2095 M: 408-234-3529 peter.tar...@sanmina-sci.com -Original Message- From: Joe Finlayson I see section 1.4.5 addressing the determination of the most unfavorable supply voltage for a test. The tolerance to be taken into account is clear for the determination of AC mains powered equipment. All it says for DC powered equipment is that the influence of polarity shall be taken into account. I see coming up with a potential of 60VDC either way. Was the intent here to state something I am missing? Thx, Joe --- 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: 48/60 Vdc Centralized Office Equipment
David, I agree that one should take into account a tolerance although I am not convinced that IEC 60950 actually addresses this (clearly anyway). Please correct me if I am mistaken as I have not investigated this situation. I see section 1.4.5 addressing the determination of the most unfavorable supply voltage for a test. The tolerance to be taken into account is clear for the determination of AC mains powered equipment. All it says for DC powered equipment is that the influence of polarity shall be taken into account. I see coming up with a potential of 60VDC either way. Was the intent here to state something I am missing? Thx, Joe -Original Message- From: David Heald [mailto:dhe...@tellium.com] Sent: Thursday, October 17, 2002 9:24 AM To: 'Peter Merguerian'; EMC-PSTC (E-mail) Subject: RE: 48/60 Vdc Centralized Office Equipment Peter, As someone who rates their products the same (well, without the label/manual discrepancy), I can say with confidence that the product is TNV-2 due to input supply deviations (60V ± a few). This isn't really as bad as it sounds, though, as the only real issue you will have is maintaining 1mm spacing around the TNV-2 circuits. Bridging components must also be of sufficient (Basic, I think, but I didn't check just now) insulation ratings, but even if they fail, the only requirement is that no more than TNV-2 voltages be present on secondary circuits or ground. Best Regards, Dave Heald -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: Wednesday, October 16, 2002 11:22 AM To: EMC-PSTC (E-mail) Subject: 48/60 Vdc Centralized Office Equipment Dear All, I have a client who insists on a 48/60 Vdc (slash) rating and wishes to consider the input to be SELV. He states in the manual the operating voltage tolerance 36-60 Vdc. In this case that the manufacturer specifies the tolerance in their manual, will the CO operators consider the 48/60 Vdc rating a SELV input; or a TNV-2 input because the float voltages on the nominal 60 Vdc supply can reach 72 Vdc - ie disregarding the specs in the manual? This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. 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 http://www.itl.co.il http://www.i-spec.com --- 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 --- 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
RE: 48/60 Vdc Centralized Office Equipment
Peter, As someone who rates their products the same (well, without the label/manual discrepancy), I can say with confidence that the product is TNV-2 due to input supply deviations (60V ± a few). This isn't really as bad as it sounds, though, as the only real issue you will have is maintaining 1mm spacing around the TNV-2 circuits. Bridging components must also be of sufficient (Basic, I think, but I didn't check just now) insulation ratings, but even if they fail, the only requirement is that no more than TNV-2 voltages be present on secondary circuits or ground. Best Regards, Dave Heald -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: Wednesday, October 16, 2002 11:22 AM To: EMC-PSTC (E-mail) Subject: 48/60 Vdc Centralized Office Equipment Dear All, I have a client who insists on a 48/60 Vdc (slash) rating and wishes to consider the input to be SELV. He states in the manual the operating voltage tolerance 36-60 Vdc. In this case that the manufacturer specifies the tolerance in their manual, will the CO operators consider the 48/60 Vdc rating a SELV input; or a TNV-2 input because the float voltages on the nominal 60 Vdc supply can reach 72 Vdc - ie disregarding the specs in the manual? This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. 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 http://www.itl.co.il http://www.i-spec.com --- 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
