RE: Conducted emissions--green wire?
Several others have questioned which standard was being applied. However, when in a situation like what you described, the best way to (hopefully) answer your questions is to state show me when the tech tells you that is the way it is done. If he / she cannot provide the standard which defines the procedure, call the supervisor, manager, boss, owner, or whoever and get the situation answered to your satisfaction. If not, you may wish to considered packing up your equipment and going home. By the way, does this lab have accreditation to ISO 17025? Regards, John Shinn, P.E. Manager, Lab Operations Sanmina-SCI john.sh...@sanmina-sci.com From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Boris Yost Sent: Monday, July 14, 2003 10:02 AM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Conducted emissions--green wire? Dear Listers: I recently watched a conducted emissions test. Said test technician connected Line to a LISN, Neutral to a LISN, and ground got stuck in a piece of foam to keep it from touching anything. This bothered me and I questioned this. However, according to said test technician, that is what they are supposed to do. The LISN's and the EUT were put on a metal table surface. The LISN's were well strapped down, but my thing was just sitting there. Doesn't this mean that the impedance of the EUT is some random number depending on the materials and surface finishes of the table, EUT, and where they put the LISN's? The stand I used for the EUT isn't really part of the EUT, just something I had to hold it up. What happens when somebody else mounts a display on a furniture lift and puts it in a piece of wooden furniture? Boris 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conducted emissions--green wire?
hehehe oh man, and it isnt even April 1st. At 12:48 14/07/2003 -0600, brent.dew...@us.datex-ohmeda.com wrote: I don't think I'd go back to that test house! What the technician did was both wrong and potentially dangerous. The closest test method to this that I know of was under the old VDE 0871 regulation in which a 50 ohm-50 microhenry network was inserted into the protective earth to lift the lead at conducted emissions frequencies. Regards, Brent DeWitt Boris Yost yost@rainbowdisplays.c To: Emc-Pstc@Majordomo. Ieee. Org emc-p...@majordomo.ieee.org om cc: Sent by: Subject: Conducted emissions--green wire? owner-emc-pstc@majordom o.ieee.org 14-07-03 11:02 AM Please respond to Boris Yost Dear Listers: I recently watched a conducted emissions test. Said test technician connected Line to a LISN, Neutral to a LISN, and ground got stuck in a piece of foam to keep it from touching anything. This bothered me and I questioned this. However, according to said test technician, that is what they are supposed to do. The LISN's and the EUT were put on a metal table surface. The LISN's were well strapped down, but my thing was just sitting there. Doesn't this mean that the impedance of the EUT is some random number depending on the materials and surface finishes of the table, EUT, and where they put the LISN's? The stand I used for the EUT isn't really part of the EUT, just something I had to hold it up. What happens when somebody else mounts a display on a furniture lift and puts it in a piece of wooden furniture? Boris --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conducted emissions--green wire?
I read in !emc-pstc that Boris Yost y...@rainbowdisplays.com wrote (in cmecjbngiaaelbblloingeomjaaa.y...@rainbowdisplays.com) about 'Conducted emissions--green wire?' on Mon, 14 Jul 2003: I recently watched a conducted emissions test. Which standard was being applied? They don't all require the same things. -- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conducted emissions--green wire?
You don't say, but I assume that the test set-up is CISPR 22 or ANSI C63.4 or some variant thereof. If it is in fact a test on equipment that mounts in a vehicle, then my answer would be quite different. Tabletop mounted equipment mounts 80 cm above ground on a non-conductive standoff. Capacitance to ground is thus not precisely controlled, but clearly limited to a few tens of pF. If the test sample is wired with a three conductor power cord, the green wire should go to ground where the LISNs are attached to ground. In fact many commercial LISNs are supplied with a female power socket designed for the standard male power plug. The green wire conductor is taken to the LISN chassis. Floor mounted equipment is also isolated from ground, although it is necessarily closer to the ground plane. Safety ground is treated same as above. From the point of view of conducted emissions, you will measure higher CE when the test sample case is directly bonded to the ground plane than when it is isolated. The mechanism for common mode conducted emissions is relying on either the green wire or the capacitance to ground to drive cm CE into ground. Differential mode emissions are unaffected by equipment case connections to ground, or the lack thereof. From: Boris Yost y...@rainbowdisplays.com Reply-To: Boris Yost y...@rainbowdisplays.com Date: Mon, 14 Jul 2003 13:02:16 -0400 To: Emc-Pstc@Majordomo. Ieee. Org emc-p...@majordomo.ieee.org Subject: Conducted emissions--green wire? Dear Listers: I recently watched a conducted emissions test. Said test technician connected Line to a LISN, Neutral to a LISN, and ground got stuck in a piece of foam to keep it from touching anything. This bothered me and I questioned this. However, according to said test technician, that is what they are supposed to do. The LISN's and the EUT were put on a metal table surface. The LISN's were well strapped down, but my thing was just sitting there. Doesn't this mean that the impedance of the EUT is some random number depending on the materials and surface finishes of the table, EUT, and where they put the LISN's? The stand I used for the EUT isn't really part of the EUT, just something I had to hold it up. What happens when somebody else mounts a display on a furniture lift and puts it in a piece of wooden furniture? Boris --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conducted emissions--green wire?
I don't think I'd go back to that test house! What the technician did was both wrong and potentially dangerous. The closest test method to this that I know of was under the old VDE 0871 regulation in which a 50 ohm-50 microhenry network was inserted into the protective earth to lift the lead at conducted emissions frequencies. Regards, Brent DeWitt Boris Yost yost@rainbowdisplays.c To: Emc-Pstc@Majordomo. Ieee. Org emc-p...@majordomo.ieee.org om cc: Sent by: Subject: Conducted emissions--green wire? owner-emc-pstc@majordom o.ieee.org 14-07-03 11:02 AM Please respond to Boris Yost Dear Listers: I recently watched a conducted emissions test. Said test technician connected Line to a LISN, Neutral to a LISN, and ground got stuck in a piece of foam to keep it from touching anything. This bothered me and I questioned this. However, according to said test technician, that is what they are supposed to do. The LISN's and the EUT were put on a metal table surface. The LISN's were well strapped down, but my thing was just sitting there. Doesn't this mean that the impedance of the EUT is some random number depending on the materials and surface finishes of the table, EUT, and where they put the LISN's? The stand I used for the EUT isn't really part of the EUT, just something I had to hold it up. What happens when somebody else mounts a display on a furniture lift and puts it in a piece of wooden furniture? Boris 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Conducted emissions--green wire?
Dear Listers: I recently watched a conducted emissions test. Said test technician connected Line to a LISN, Neutral to a LISN, and ground got stuck in a piece of foam to keep it from touching anything. This bothered me and I questioned this. However, according to said test technician, that is what they are supposed to do. The LISN's and the EUT were put on a metal table surface. The LISN's were well strapped down, but my thing was just sitting there. Doesn't this mean that the impedance of the EUT is some random number depending on the materials and surface finishes of the table, EUT, and where they put the LISN's? The stand I used for the EUT isn't really part of the EUT, just something I had to hold it up. What happens when somebody else mounts a display on a furniture lift and puts it in a piece of wooden furniture? Boris 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
