Re: Do I need to Test for Harmonics?
I read in !emc-pstc that Scott Douglas dougl...@naradnetworks.com wrote (in 5.0.2.1.2.20021022080058.00a69...@pop.business.earthlink.net ) about 'Do I need to Test for Harmonics?' on Tue, 22 Oct 2002: One argument says that we are not connected to the public low-voltage distribution system, instead the ferroresonant supply is. Therefore, since we ARE NOT connected we do not need to do the harmonics test. That is most probably the case. What matters is what is emitted into the public supply. The flip side argument says that we still have to test harmonics because the supply does nothing but provide power to our product and therefore we ARE connected. That's not the point at all, I suspect. Is there any significant correlation between the harmonic current amplitudes at the output of the ferroresonant supply and those at its input? If not, there is absolutely no point in measuring those at its output, which are not those that are emitted into the public supply. Understand that this system consists of power supplies and amplifiers, etc. from one or more than one supplier (read that more than one manufacturer). We cannot guarantee we are the sole provider here, in fact will most likely not be the sole provider. Especially since we do not manufacture or sell power supplies. It isn't a 'system' in the sense of the EMC Directive unless the whole thing is supplied as a single article of commerce, i.e. one single item on the invoice. You are only concerned with your own product. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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: Do I need to Test for Harmonics?
I would agree with your argument that you need not comply because you are not connected to the public low voltage supply. Furthermore, the standards you cite are written for 230V, 50Hz distribution, so your voltage is not even within the scope of the standard. John P. Wagner Regulatory Compliance Mandatory Standards AVAYA Strategic Standards. 1300 W. 120th Ave, Room B3-D16 Westminster, CO 80234-2726 Phone/Fax: (303) 538-4241 johnwag...@avaya.com -- From: Scott Douglas[SMTP:dougl...@naradnetworks.com] Reply To: Scott Douglas Sent: Tuesday, October 22, 2002 5:02 AM To: emc-p...@ieee.org Subject: Do I need to Test for Harmonics? Fellow Listees: There were some recent threads regarding what testing is required for a product that obtains power from a supply external to the product and maybe not supplied by the manufacturer. I think the questions were related to EFT or surge. I have a similar situation. Our products are network powered; that is, there is a ferroresonant power supply connected to the network and we just tap into that available power. This is CATV land and not Telco. We do not make the supply nor do we sell them. Our products have switching supplies which run on the quasi-square wave provided by the ferroresonant supply. Voltage of the supply is in the 60-90 VAC range. Question is: EN 50083-2 : 2001 (4.1.2 Disturbance Voltages From Equipment...) says that if our products fall within the input current range of EN 61000-3-2, then the tests and limits of that standard apply. Then EN 61000-3-2 : 2000 (1. Scope) says that the standard applies to products intended to be connected to public low-voltage distribution systems. One argument says that we are not connected to the public low-voltage distribution system, instead the ferroresonant supply is. Therefore, since we ARE NOT connected we do not need to do the harmonics test. The flip side argument says that we still have to test harmonics because the supply does nothing but provide power to our product and therefore we ARE connected. Understand that this system consists of power supplies and amplifiers, etc. from one or more than one supplier (read that more than one manufacturer). We cannot guarantee we are the sole provider here, in fact will most likely not be the sole provider. Especially since we do not manufacture or sell power supplies. So all powerful and wise list, what's a mother to do? Do I, or do I not, test? Am I required to test? Have I missed something? Thanks for all of the wisdom you are about to impart. Regards, Scott Douglas Senior Compliance Engineer Narad Networks 515 Groton Road Westford, MA 01886 phone: 978 589-1869 dougl...@naradnetworks.com www.naradnetworks.com http://www.naradnetworks.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
RE: Do I need to Test for Harmonics?
Scott, you do not have to test for power line harmonics or flicker if 1) your product is not mains powered, and 2) you have no intention of selling it along with a particular power source, and 3) you do not specify that it be used with a particular power source. If the choice of power source is up to the system manufacturer, he is responsible for compliance of the system including all of its variants. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: Scott Douglas [mailto:dougl...@naradnetworks.com] Sent: Tuesday, October 22, 2002 8:02 AM To: emc-p...@ieee.org Subject: Do I need to Test for Harmonics? Fellow Listees: There were some recent threads regarding what testing is required for a product that obtains power from a supply external to the product and maybe not supplied by the manufacturer. I think the questions were related to EFT or surge. I have a similar situation. Our products are network powered; that is, there is a ferroresonant power supply connected to the network and we just tap into that available power. This is CATV land and not Telco. We do not make the supply nor do we sell them. Our products have switching supplies which run on the quasi-square wave provided by the ferroresonant supply. Voltage of the supply is in the 60-90 VAC range. Question is: EN 50083-2 : 2001 (4.1.2 Disturbance Voltages From Equipment...) says that if our products fall within the input current range of EN 61000-3-2, then the tests and limits of that standard apply. Then EN 61000-3-2 : 2000 (1. Scope) says that the standard applies to products intended to be connected to public low-voltage distribution systems. One argument says that we are not connected to the public low-voltage distribution system, instead the ferroresonant supply is. Therefore, since we ARE NOT connected we do not need to do the harmonics test. The flip side argument says that we still have to test harmonics because the supply does nothing but provide power to our product and therefore we ARE connected. Understand that this system consists of power supplies and amplifiers, etc. from one or more than one supplier (read that more than one manufacturer). We cannot guarantee we are the sole provider here, in fact will most likely not be the sole provider. Especially since we do not manufacture or sell power supplies. So all powerful and wise list, what's a mother to do? Do I, or do I not, test? Am I required to test? Have I missed something? Thanks for all of the wisdom you are about to impart. Regards, Scott Douglas Senior Compliance Engineer Narad Networks 515 Groton Road Westford, MA 01886 phone: 978 589-1869 dougl...@naradnetworks.com www.naradnetworks.com http://www.naradnetworks.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
Do I need to Test for Harmonics?
Fellow Listees: There were some recent threads regarding what testing is required for a product that obtains power from a supply external to the product and maybe not supplied by the manufacturer. I think the questions were related to EFT or surge. I have a similar situation. Our products are network powered; that is, there is a ferroresonant power supply connected to the network and we just tap into that available power. This is CATV land and not Telco. We do not make the supply nor do we sell them. Our products have switching supplies which run on the quasi-square wave provided by the ferroresonant supply. Voltage of the supply is in the 60-90 VAC range. Question is: EN 50083-2 : 2001 (4.1.2 Disturbance Voltages From Equipment...) says that if our products fall within the input current range of EN 61000-3-2, then the tests and limits of that standard apply. Then EN 61000-3-2 : 2000 (1. Scope) says that the standard applies to products intended to be connected to public low-voltage distribution systems. One argument says that we are not connected to the public low-voltage distribution system, instead the ferroresonant supply is. Therefore, since we ARE NOT connected we do not need to do the harmonics test. The flip side argument says that we still have to test harmonics because the supply does nothing but provide power to our product and therefore we ARE connected. Understand that this system consists of power supplies and amplifiers, etc. from one or more than one supplier (read that more than one manufacturer). We cannot guarantee we are the sole provider here, in fact will most likely not be the sole provider. Especially since we do not manufacture or sell power supplies. So all powerful and wise list, what's a mother to do? Do I, or do I not, test? Am I required to test? Have I missed something? Thanks for all of the wisdom you are about to impart. Regards, Scott Douglas Senior Compliance Engineer Narad Networks 515 Groton Road Westford, MA 01886 phone: 978 589-1869 dougl...@naradnetworks.com www.naradnetworks.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"
