Re: [PSES] EU's new approach directive transitions

[Charlie Blackham]

Ron

Few short answers:


* No sign of that happening at all and I cannot see it happening

* No, existing Directives are repealed by the new Directives on the 
dates indicated,  but you may wish to look at Recommended format for DoC that 
can reference existing and new Directives, 
http://ec.europa.eu/DocsRoom/documents/14886/attachments/1/translations/en/renditions/native
  (referenced from 
http://ec.europa.eu/growth/sectors/electrical-engineering/emc-directive/index_en.htm
 )

* ETSI are working hard on updating over 150 standards, some more 
information available:

o   https://docbox.etsi.org/Workshop/2015/201511_RED-WORKSHOP/ for 
presentations from November workshop

o   Work program on radio standards: 
http://webapp.etsi.org/ena/cvp.asp?search=RADIO and a number of RED standards 
have a been published or are available as final draft

o   Work program on EMC standards: 
http://webapp.etsi.org/ena/cvp.asp?Search=emc&Status=&Directive=&submit1=Get+Work+Items

* Lists of HS for current standards can be used for new Directives 
until new lists are published as per relevant article in the directive such as 
article 27 of the 2014/35/EU LVD.

* So far I'm aware of:

o   LVD guidance on transition to new LVD, 
http://ec.europa.eu/DocsRoom/documents/13141/attachments/1/translations/en/renditions/native
 available at 
http://ec.europa.eu/growth/sectors/electrical-engineering/lvd-directive/index_en.htm

o   RED guidance is being worked on, but RED is not mandatory until 2017 so 
there is more time for this.  
http://ec.europa.eu/DocsRoom/documents/11983/attachments/1/translations/en/renditions/pdf
 provides guidance on transitions for equipment moving into and out of 
R&TTE/RED.

* No one is expecting anything.

Regards
Charlie

Charlie Blackham
Sulis Consultants Ltd
Tel: +44 (0)7946 624317
LinkedIn: 
uk.linkedin.com/in/charlieblackham/
Web: www.sulisconsultants.com
Registered in England and Wales, number 05466247



From: Ronald Pickard [mailto:ronald.pick...@compoundphotonics.com]
Sent: 29 March 2016 23:46
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] EU's new approach directive transitions

Hi to all, and especially to those that are knowledgeable of the EU's processes 
on this subject,

I know that this subject has been discussed before without resolution, but the 
time is nearing the end of the transition periods of the EU's new EMC, LV and 
RE directives and I (I'm guessing I'm not alone) was wondering if anyone knows 
what the EU intends to do when these directives reach beyond their respective 
transition periods with no listed harmonized standards?

- Will the directives' transition dates be extended?
- Will a presumption of conformity continue to exist to the repealed directives 
after the transition period?
- What is ETSI's timeline to revise its harmonized standards to reflect these 
new directives?
- Will harmonized standards under the current respective directives continue to 
be utilized under the new directives (probable)?
- Is there any EU guidance that addresses the above questions? If so, please 
provide a link(s).
- Will the EU pull a rabbit out of its hat at the last moment?

Can anyone shed any light on this?

I look forward to your reply.

Best regards,

Ron Pickard
Regulatory Compliance Engineer
Compound Photonics
D | +1 (602) 883-8039

-


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This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses

[PSES] EMCD: Alternatives to Harmonized Standards?

[Mike Sherman ----- Original Message -----]

The new EMC Directive refers briefly to the option of applying "other relevant 
technical standards" in place of harmonized standards. 

I'm looking at some electrical construction equipment whose use might be best 
described as some combination of light and heavy industrial. 

Does anyone have any experience or advice in applying "other relevant technical 
standards" in place of harmonized standards for such products? 

thanks, 
Mike Sherman 
Graco Inc. 

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Ken Javor]

This is a mathematical construct.  The reality is that cm and dm flow in the
same direction on one conductor and in the opposite direction on the other
conductor. Aside from that any additional phasing doesn¹t seem physically
real.

Ken Javor
Ph. (256) 650-5261 




From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 23:08:43 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

Sorry for all the typos in that last one and the repeat. When writing
equations, typos are pretty confusing to a reader, so I updated the
important part below with corrected maths. Basically, if |L| and |N| are
almost equal on your SA or EMI receiver (not L and N, |L| and |N|), this
tells you absolutely nothing about DM and CM relative to each other.
 

 
We¹ll define L = DM + CM and N = DM - CM
 
To prove the point above
Let¹s suppose CM = jDM
then
|L |= |DM + CM| = |DM + jDM| = sqrt2 *|DM|
|N| = |DM ­ CM| = |DM ­ jDM| = sqrt2 *|DM|
Therefore |L| = |N| even though |DM| = |CM|
 
Elliott Martinson
 
 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 5:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN
 
Back in the 1990s I presented a paper where I used LISNMATE to isolate cm
emissions using an o¹scope and using an FFT routine on the scope data, could
get decent frequency domain info on the cm data, and built a filter this
way.  Without the DMRN (differential mode rejection network ­ generic name)
this was impossible. Because cm is related to the waveform rise time, the
output on the scope was clearly visible for what it was, and the filter
design by modes went very smoothly. Not saying this is the way to go, but it
is/was possible.

Ken Javor
Ph. (256) 650-5261 


From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 21:59:10 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

I understand what you are saying. And if we¹re using scopes to view the
time-domain waveform and measuring simultaneously, MATH functions will make
this easy. But noise is chaotic, and subsequent measurements of the L
conductor only won¹t even be exactly the same. The phase relationships of
different noise signals from different sources in the device are constantly
changing depending on when the measurement was made as well. Again, I¹m
assuming an SA or EMI receiver here.
 
I¹m probably way overthinking this K

 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

On one conductor, cm and dm sum, and on the other, they subtract. If a sum
and difference of two quantities is equal, it can only be because one of
them is zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261 


From: Elliott Martinson 
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor , "EMC-PSTC@LISTSERV.IEEE.ORG"

Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and
LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.
 
As for the current probes, comparing L and N to determine if one of cm or dm
predominatesŠ we are talking about noise signals, and measuring magnitudes
(no phase info) in frequency domain, right? I know that on one conductor,
you can say CM/DM add while they subtract on the other (mathematically
correct no matter which you call L and which you call N). I¹m confused at
how you know it cannot be similar amounts CM and DM noise when the noise
magnitude is the same between L and N. I¹d appreciate it if you could
explain.
 
Obviously running L+N simultaneously through the same probe gives
common-mode noise, I¹m not sure if I worded my response badly because I
meant to say bullet #3 is completely correct (as is 1, along with 4 assuming
no ³LISNMATE²)
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

Disagree. Westin had it right. A current probe can be used to isolate either
cm or dm current. If at any frequency the signal amplitude on individual
line and neutral conductors are very close, then all you can say is that at
that frequency either cm or dm predominates, but you can¹t say which.  With
a LISN, a separate device must be used. Mark Nave of EMC Services designed a
t

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Elliott Martinson]

Sorry for all the typos in that last one and the repeat. When writing 
equations, typos are pretty confusing to a reader, so I updated the important 
part below with corrected maths. Basically, if |L| and |N| are almost equal on 
your SA or EMI receiver (not L and N, |L| and |N|), this tells you absolutely 
nothing about DM and CM relative to each other.


We'll define L = DM + CM and N = DM - CM

To prove the point above
Let's suppose CM = jDM
then
|L |= |DM + CM| = |DM + jDM| = sqrt2 *|DM|
|N| = |DM - CM| = |DM - jDM| = sqrt2 *|DM|
Therefore |L| = |N| even though |DM| = |CM|

Elliott Martinson


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 5:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Back in the 1990s I presented a paper where I used LISNMATE to isolate cm 
emissions using an o'scope and using an FFT routine on the scope data, could 
get decent frequency domain info on the cm data, and built a filter this way.  
Without the DMRN (differential mode rejection network - generic name) this was 
impossible. Because cm is related to the waveform rise time, the output on the 
scope was clearly visible for what it was, and the filter design by modes went 
very smoothly. Not saying this is the way to go, but it is/was possible.

Ken Javor
Ph. (256) 650-5261


From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Reply-To: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 21:59:10 +
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

I understand what you are saying. And if we're using scopes to view the 
time-domain waveform and measuring simultaneously, MATH functions will make 
this easy. But noise is chaotic, and subsequent measurements of the L conductor 
only won't even be exactly the same. The phase relationships of different noise 
signals from different sources in the device are constantly changing depending 
on when the measurement was made as well. Again, I'm assuming an SA or EMI 
receiver here.

I'm probably way overthinking this :|



From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

On one conductor, cm and dm sum, and on the other, they subtract. If a sum and 
difference of two quantities is equal, it can only be because one of them is 
zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261


From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor 
mailto:ken.ja...@emccompliance.com>>, 
"EMC-PSTC@LISTSERV.IEEE.ORG" 
mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.

As for the current probes, comparing L and N to determine if one of cm or dm 
predominates... we are talking about noise signals, and measuring magnitudes 
(no phase info) in frequency domain, right? I know that on one conductor, you 
can say CM/DM add while they subtract on the other (mathematically correct no 
matter which you call L and which you call N). I'm confused at how you know it 
cannot be similar amounts CM and DM noise when the noise magnitude is the same 
between L and N. I'd appreciate it if you could explain.

Obviously running L+N simultaneously through the same probe gives common-mode 
noise, I'm not sure if I worded my response badly because I meant to say bullet 
#3 is completely correct (as is 1, along with 4 assuming no "LISNMATE")


Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
mailto:elliott.martin...@etcconnect.com>>


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Disagree. Westin had it right. A current probe can be used to isolate either cm 
or dm current. If at any frequency the signal amplitude on individual line and 
neutral conductors are very close, then all you can say is that at that 
frequency either cm or dm predominates, but you can't say which.  With a LISN, 
a separate device must be used. Mark Nave of EMC Service

[PSES] EU's new approach directive transitions

[Ronald Pickard]

Hi to all, and especially to those that are knowledgeable of the EU's processes 
on this subject,

I know that this subject has been discussed before without resolution, but the 
time is nearing the end of the transition periods of the EU's new EMC, LV and 
RE directives and I (I'm guessing I'm not alone) was wondering if anyone knows 
what the EU intends to do when these directives reach beyond their respective 
transition periods with no listed harmonized standards?

- Will the directives' transition dates be extended?
- Will a presumption of conformity continue to exist to the repealed directives 
after the transition period?
- What is ETSI's timeline to revise its harmonized standards to reflect these 
new directives?
- Will harmonized standards under the current respective directives continue to 
be utilized under the new directives (probable)?
- Is there any EU guidance that addresses the above questions? If so, please 
provide a link(s).
- Will the EU pull a rabbit out of its hat at the last moment?

Can anyone shed any light on this?

I look forward to your reply.

Best regards,

Ron Pickard
Regulatory Compliance Engineer
Compound Photonics
D | +1 (602) 883-8039


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Elliott Martinson]

I was about to post about discovering my "erroneous" line of thinking. 
Something similar to what follows:
Line has combination of DM and CM, lets say L = DM + CM
Neutral has combination of DM and CM, lets say N = DM - CM

Then, when converting to magnitude, my mind said
L = ||DM| + |CM|| and
N = ||DM| + |-CM|| = ||DM| + |DM||
Therefore L = N

In reality, it's
L =|DM + CM| and
N = |DM - CM|

If DM is similar to CM or (-CM) then it initially appears that the magnitudes 
of L and N cannot be the same barring a zero signal.

EXCEPT-

After yet even further thought, I have discovered a very simple counterexample.

Let's say DM = jCM, and |DM| = |CM|

L = |DM + jCM|
N = |DM - jCM|
Since DM and CM are orthogonal, |L| = |DM + jCM| = ||DM| + |jCM|| = ||DM| + 
|-jCM|| = N

Elliott Martinson


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 5:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Back in the 1990s I presented a paper where I used LISNMATE to isolate cm 
emissions using an o'scope and using an FFT routine on the scope data, could 
get decent frequency domain info on the cm data, and built a filter this way.  
Without the DMRN (differential mode rejection network - generic name) this was 
impossible. Because cm is related to the waveform rise time, the output on the 
scope was clearly visible for what it was, and the filter design by modes went 
very smoothly. Not saying this is the way to go, but it is/was possible.

Ken Javor
Ph. (256) 650-5261



From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Reply-To: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 21:59:10 +
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

I understand what you are saying. And if we're using scopes to view the 
time-domain waveform and measuring simultaneously, MATH functions will make 
this easy. But noise is chaotic, and subsequent measurements of the L conductor 
only won't even be exactly the same. The phase relationships of different noise 
signals from different sources in the device are constantly changing depending 
on when the measurement was made as well. Again, I'm assuming an SA or EMI 
receiver here.

I'm probably way overthinking this :|



From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

On one conductor, cm and dm sum, and on the other, they subtract. If a sum and 
difference of two quantities is equal, it can only be because one of them is 
zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261


From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor 
mailto:ken.ja...@emccompliance.com>>, 
"EMC-PSTC@LISTSERV.IEEE.ORG" 
mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.

As for the current probes, comparing L and N to determine if one of cm or dm 
predominates... we are talking about noise signals, and measuring magnitudes 
(no phase info) in frequency domain, right? I know that on one conductor, you 
can say CM/DM add while they subtract on the other (mathematically correct no 
matter which you call L and which you call N). I'm confused at how you know it 
cannot be similar amounts CM and DM noise when the noise magnitude is the same 
between L and N. I'd appreciate it if you could explain.

Obviously running L+N simultaneously through the same probe gives common-mode 
noise, I'm not sure if I worded my response badly because I meant to say bullet 
#3 is completely correct (as is 1, along with 4 assuming no "LISNMATE")


Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
mailto:elliott.martin...@etcconnect.com>>


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Disagree. Westin had it right. A current probe can be used to isolate either cm 
or dm current. If at any frequency the signal amplitude on individual line and 
neutral c

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Ken Javor]

Back in the 1990s I presented a paper where I used LISNMATE to isolate cm
emissions using an o¹scope and using an FFT routine on the scope data, could
get decent frequency domain info on the cm data, and built a filter this
way.  Without the DMRN (differential mode rejection network ­ generic name)
this was impossible. Because cm is related to the waveform rise time, the
output on the scope was clearly visible for what it was, and the filter
design by modes went very smoothly. Not saying this is the way to go, but it
is/was possible.

Ken Javor
Ph. (256) 650-5261 




From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 21:59:10 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

I understand what you are saying. And if we¹re using scopes to view the
time-domain waveform and measuring simultaneously, MATH functions will make
this easy. But noise is chaotic, and subsequent measurements of the L
conductor only won¹t even be exactly the same. The phase relationships of
different noise signals from different sources in the device are constantly
changing depending on when the measurement was made as well. Again, I¹m
assuming an SA or EMI receiver here.
 
I¹m probably way overthinking this K
 
 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN
 
On one conductor, cm and dm sum, and on the other, they subtract. If a sum
and difference of two quantities is equal, it can only be because one of
them is zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261 



From: Elliott Martinson 
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor , "EMC-PSTC@LISTSERV.IEEE.ORG"

Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and
LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.
 
As for the current probes, comparing L and N to determine if one of cm or dm
predominatesŠ we are talking about noise signals, and measuring magnitudes
(no phase info) in frequency domain, right? I know that on one conductor,
you can say CM/DM add while they subtract on the other (mathematically
correct no matter which you call L and which you call N). I¹m confused at
how you know it cannot be similar amounts CM and DM noise when the noise
magnitude is the same between L and N. I¹d appreciate it if you could
explain.
 
Obviously running L+N simultaneously through the same probe gives
common-mode noise, I¹m not sure if I worded my response badly because I
meant to say bullet #3 is completely correct (as is 1, along with 4 assuming
no ³LISNMATE²)
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

Disagree. Westin had it right. A current probe can be used to isolate either
cm or dm current. If at any frequency the signal amplitude on individual
line and neutral conductors are very close, then all you can say is that at
that frequency either cm or dm predominates, but you can¹t say which.  With
a LISN, a separate device must be used. Mark Nave of EMC Services designed a
three port device (connects to each LISN port and to the EMI receiver)
trademarked LISNMATE in the 1980s to isolate common mode, and sometime later
he produced LISNMARK, which isolated DM.  Within the past decade, Ray Adams
while at Fischer Custom Communications packed both functions in one piece of
equipment, which if memory serves was named LISNUP.

EMC Services, Mark Nave¹s company, is no longer producing his products, but
I believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261 


From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 20:36:18 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.
 
Your second point kind of contradicts your first, if it¹s trying to say what
I think it is. DM and CM each show up on L, but the same is true for N. It¹s
a linear combination of both, so even if L and N are almost equal, you can¹t
say anything about the proportion of DM to CM currents.
 
If they are not equal, then this implies current is travelling back via the
ground conductor and/or energy¹s being lost to radiated emissions.
 
What you ne

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Elliott Martinson]

I understand what you are saying. And if we're using scopes to view the 
time-domain waveform and measuring simultaneously, MATH functions will make 
this easy. But noise is chaotic, and subsequent measurements of the L conductor 
only won't even be exactly the same. The phase relationships of different noise 
signals from different sources in the device are constantly changing depending 
on when the measurement was made as well. Again, I'm assuming an SA or EMI 
receiver here.

I'm probably way overthinking this :|


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:51 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

On one conductor, cm and dm sum, and on the other, they subtract. If a sum and 
difference of two quantities is equal, it can only be because one of them is 
zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261



From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor 
mailto:ken.ja...@emccompliance.com>>, 
"EMC-PSTC@LISTSERV.IEEE.ORG" 
mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.

As for the current probes, comparing L and N to determine if one of cm or dm 
predominates... we are talking about noise signals, and measuring magnitudes 
(no phase info) in frequency domain, right? I know that on one conductor, you 
can say CM/DM add while they subtract on the other (mathematically correct no 
matter which you call L and which you call N). I'm confused at how you know it 
cannot be similar amounts CM and DM noise when the noise magnitude is the same 
between L and N. I'd appreciate it if you could explain.

Obviously running L+N simultaneously through the same probe gives common-mode 
noise, I'm not sure if I worded my response badly because I meant to say bullet 
#3 is completely correct (as is 1, along with 4 assuming no "LISNMATE")


Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
mailto:elliott.martin...@etcconnect.com>>


From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Disagree. Westin had it right. A current probe can be used to isolate either cm 
or dm current. If at any frequency the signal amplitude on individual line and 
neutral conductors are very close, then all you can say is that at that 
frequency either cm or dm predominates, but you can't say which.  With a LISN, 
a separate device must be used. Mark Nave of EMC Services designed a three port 
device (connects to each LISN port and to the EMI receiver) trademarked 
LISNMATE in the 1980s to isolate common mode, and sometime later he produced 
LISNMARK, which isolated DM.  Within the past decade, Ray Adams while at 
Fischer Custom Communications packed both functions in one piece of equipment, 
which if memory serves was named LISNUP.

EMC Services, Mark Nave's company, is no longer producing his products, but I 
believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261


From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Reply-To: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 20:36:18 +
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.

Your second point kind of contradicts your first, if it's trying to say what I 
think it is. DM and CM each show up on L, but the same is true for N. It's a 
linear combination of both, so even if L and N are almost equal, you can't say 
anything about the proportion of DM to CM currents.

If they are not equal, then this implies current is travelling back via the 
ground conductor and/or energy's being lost to radiated emissions.

What you need is a physical circuit to do the adding/subtracting of the LISN 
outputs. (otherwise your 3rd bullet point is correct)

Your 4th bullet, well I refer you to the link above.


Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@e

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Ken Javor]

The report on which the old 48 dBuV class B CE limit was based did develop
that based on the conducted susceptibility of AM and shortwave radios, but
it also noted that limit functioned as an adequate control for common mode
noise that would radiate as per Doug¹s observation. Back in the late Œ90s I
presented a detailed test report to TC77 showing that if instead of
controlling conducted emissions at each LISN port, they instead controlled
by modes, that dm could be relaxed 20 dB to 68 dBuV and the committee took
an action item and back then said if that were implemented, it would save
the power supply industry $35 million a year.  The work I did was based on
using the LISNMATE / LISNMARK technology as injection tools injecting pure
cm and dm and showing that the susceptibility to dm was 20 dB less, because
of bulk filter caps on the secondary of power supplies, whereas there were
no Y-caps and no cm filtering. The reason this was missed back in 1977/78
when the report was written was they used a single LISN with neutral through
the case.  CM and DM flowed in the same path.

Ken Javor
Ph. (256) 650-5261 




From: Doug Smith 
Reply-To: 
Date: Tue, 29 Mar 2016 14:31:20 -0700
To: , Ken Javor 
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

Hi Ken and the group,

 

I always thought that the FCC measures the wrong quantity for conducted
emmissions. What shoud be measured is all conductors (two or three including
phase/neutral/protective earth) together as common mode current as that is
what radiates from the long power lines causing problems for shortwave
receivers and Amateur Radio Operators. The old demonstration of conducted
EMI into AM radios is not so useful, especially today.

 

Below 30 MHz, most devices are not large enough to radiate efficiently, but
the power wiring is long enough to radiate. I have a case of EMI in my house
from two Feit Electric LED floodlights that meet conducted emissions, but I
can't use a hand held, battery powered, shortwave receiver when the two are
on except to walk quite a distance from that part of the house. The FCC test
may catch this case, but apparently not for me, as there are only two wires
but that is not the case for other devices.

 

So phase+neutral could be noisy with respect to protective earth but as long
as it is balanced by an opposite current on protective earth, radiation
should be low.

 

Any other Amateur Radio operators want to weigh in on this?

 

Doug (K4OAP, since 1959)

 






On Tue, 29 Mar 2016 16:13:58 -0500, Ken Javor 
wrote:
> 
> Re: [PSES] Commom mode current vs. differential mode current and LISN
> Disagree. Westin had it right. A current probe can be used to isolate either
> cm or dm current. If at any frequency the signal amplitude on individual line
> and neutral conductors are very close, then all you can say is that at that
> frequency either cm or dm predominates, but you can¹t say which.  With a LISN,
> a separate device must be used. Mark Nave of EMC Services designed a three
> port device (connects to each LISN port and to the EMI receiver) trademarked
> LISNMATE in the 1980s to isolate common mode, and sometime later he produced
> LISNMARK, which isolated DM.  Within the past decade, Ray Adams while at
> Fischer Custom Communications packed both functions in one piece of equipment,
> which if memory serves was named LISNUP.
> 
>  EMC Services, Mark Nave¹s company, is no longer producing his products, but I
> believe the FCC product is still available.
> 
>  Ken Javor
>  Ph. (256) 650-5261
> 
> 
> 
> 
> From: Elliott Martinson 
> Reply-To: Elliott Martinson 
> Date: Tue, 29 Mar 2016 20:36:18 +
> To: 
> Conversation: [PSES] Commom mode current vs. differential mode current and
> LISN
> Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN
> 
> http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
> This is a great resource for your question.
>   
>  Your second point kind of contradicts your first, if it¹s trying to say what
> I think it is. DM and CM each show up on L, but the same is true for N. It¹s a
> linear combination of both, so even if L and N are almost equal, you can¹t say
> anything about the proportion of DM to CM currents.
>   
>  If they are not equal, then this implies current is travelling back via the
> ground conductor and/or energy¹s being lost to radiated emissions.
>   
>  What you need is a physical circuit to do the adding/subtracting of the LISN
> outputs. (otherwise your 3rd bullet point is correct)
>   
>  Your 4th bullet, well I refer you to the link above.
>   
> 
> Elliott Martinson
> Product Assurance Specialist I
> Electronic Theatre Controls
> 3031 N PLEASANT VIEW RD
>  MIDDLETON WI 53562-4809
> Work: 608.824.5696 / Cell: 608.209.9897
> elliott.martin...@etcconnect.com 
>   
> 
> From: Amund Westin [mailto:am...@westin-emission.no]
> 
> Sent: Tuesday, March 29, 2016 1:23 PM
> To: 

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Elliott Martinson]

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.

As for the current probes, comparing L and N to determine if one of cm or dm 
predominates... we are talking about noise signals, and measuring magnitudes 
(no phase info) in frequency domain, right? I know that on one conductor, you 
can say CM/DM add while they subtract on the other (mathematically correct no 
matter which you call L and which you call N). I'm confused at how you know it 
cannot be similar amounts CM and DM noise when the noise magnitude is the same 
between L and N. I'd appreciate it if you could explain.

Obviously running L+N simultaneously through the same probe gives common-mode 
noise, I'm not sure if I worded my response badly because I meant to say bullet 
#3 is completely correct (as is 1, along with 4 assuming no "LISNMATE")

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

Disagree. Westin had it right. A current probe can be used to isolate either cm 
or dm current. If at any frequency the signal amplitude on individual line and 
neutral conductors are very close, then all you can say is that at that 
frequency either cm or dm predominates, but you can't say which.  With a LISN, 
a separate device must be used. Mark Nave of EMC Services designed a three port 
device (connects to each LISN port and to the EMI receiver) trademarked 
LISNMATE in the 1980s to isolate common mode, and sometime later he produced 
LISNMARK, which isolated DM.  Within the past decade, Ray Adams while at 
Fischer Custom Communications packed both functions in one piece of equipment, 
which if memory serves was named LISNUP.

EMC Services, Mark Nave's company, is no longer producing his products, but I 
believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261



From: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Reply-To: Elliott Martinson 
mailto:elliott.martin...@etcconnect.com>>
Date: Tue, 29 Mar 2016 20:36:18 +
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG>>
Conversation: [PSES] Commom mode current vs. differential mode current and LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.

Your second point kind of contradicts your first, if it's trying to say what I 
think it is. DM and CM each show up on L, but the same is true for N. It's a 
linear combination of both, so even if L and N are almost equal, you can't say 
anything about the proportion of DM to CM currents.

If they are not equal, then this implies current is travelling back via the 
ground conductor and/or energy's being lost to radiated emissions.

What you need is a physical circuit to do the adding/subtracting of the LISN 
outputs. (otherwise your 3rd bullet point is correct)

Your 4th bullet, well I refer you to the link above.


Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
mailto:elliott.martin...@etcconnect.com>>


From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Tuesday, March 29, 2016 1:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Commom mode current vs. differential mode current and LISN

Please correct me, if I am wrong (that happens quite often ...):

*Let one wire (L) pass through a current clamp, and you measure the 
combination of current mode and differential mode currents

*Do the same with wire N. If L and N are (almost) equal, you either 
have major part of DM currents or major part of CM current

*Let both wire (L and N) pass through a current clamp, and you measure 
the only CM current (DM is canceled)

* When doing conducted emission test by LISN, you actually get what you 
get. LISN do not see the difference between CM or DM. From LISN measurements, 
you can't say if noise is CM or DM.

B.regards

Amund













-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
mailto:emc-p...@ieee.org>>

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Ken Javor]

On one conductor, cm and dm sum, and on the other, they subtract. If a sum
and difference of two quantities is equal, it can only be because one of
them is zero (or much less than the other).

Ken Javor
Ph. (256) 650-5261 




From: Elliott Martinson 
Date: Tue, 29 Mar 2016 21:37:42 +
To: Ken Javor , "EMC-PSTC@LISTSERV.IEEE.ORG"

Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: RE: [PSES] Commom mode current vs. differential mode current and
LISN

The LISNMARK (LISN MATE) is exactly the same device as what I linked to.
 
As for the current probes, comparing L and N to determine if one of cm or dm
predominatesŠ we are talking about noise signals, and measuring magnitudes
(no phase info) in frequency domain, right? I know that on one conductor,
you can say CM/DM add while they subtract on the other (mathematically
correct no matter which you call L and which you call N). I¹m confused at
how you know it cannot be similar amounts CM and DM noise when the noise
magnitude is the same between L and N. I¹d appreciate it if you could
explain.
 
Obviously running L+N simultaneously through the same probe gives
common-mode noise, I¹m not sure if I worded my response badly because I
meant to say bullet #3 is completely correct (as is 1, along with 4 assuming
no ³LISNMATE²)
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
 

From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Tuesday, March 29, 2016 4:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN
 
Disagree. Westin had it right. A current probe can be used to isolate either
cm or dm current. If at any frequency the signal amplitude on individual
line and neutral conductors are very close, then all you can say is that at
that frequency either cm or dm predominates, but you can¹t say which.  With
a LISN, a separate device must be used. Mark Nave of EMC Services designed a
three port device (connects to each LISN port and to the EMI receiver)
trademarked LISNMATE in the 1980s to isolate common mode, and sometime later
he produced LISNMARK, which isolated DM.  Within the past decade, Ray Adams
while at Fischer Custom Communications packed both functions in one piece of
equipment, which if memory serves was named LISNUP.

EMC Services, Mark Nave¹s company, is no longer producing his products, but
I believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261 



From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 20:36:18 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.
 
Your second point kind of contradicts your first, if it¹s trying to say what
I think it is. DM and CM each show up on L, but the same is true for N. It¹s
a linear combination of both, so even if L and N are almost equal, you can¹t
say anything about the proportion of DM to CM currents.
 
If they are not equal, then this implies current is travelling back via the
ground conductor and/or energy¹s being lost to radiated emissions.
 
What you need is a physical circuit to do the adding/subtracting of the LISN
outputs. (otherwise your 3rd bullet point is correct)
 
Your 4th bullet, well I refer you to the link above.
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
 

From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Tuesday, March 29, 2016 1:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Commom mode current vs. differential mode current and LISN

Please correct me, if I am wrong (that happens quite often Š):

·Let one wire (L) pass through a current clamp, and you measure the
combination of current mode and differential mode currents

·Do the same with wire N. If L and N are (almost) equal, you either
have major part of DM currents or major part of CM current

·Let both wire (L and N) pass through a current clamp, and you
measure the only CM current (DM is canceled)

· When doing conducted emission test by LISN, you actually get what
you get. LISN do not see the difference between CM or DM. From LISN
measurements, you can¹t say if noise is CM or DM.

B.regards

Amund













-

This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Doug Smith]

Hi Ken and the group,
 
I always thought that the FCC measures the wrong quantity for conducted
emmissions. What shoud be measured is all conductors (two or three
including phase/neutral/protective earth) together as common mode
current as that is what radiates from the long power lines causing
problems for shortwave receivers and Amateur Radio Operators. The old
demonstration of conducted EMI into AM radios is not so useful,
especially today.
 
Below 30 MHz, most devices are not large enough to radiate efficiently,
but the power wiring is long enough to radiate. I have a case of EMI in
my house from two Feit Electric LED floodlights that meet conducted
emissions, but I can't use a hand held, battery powered, shortwave
receiver when the two are on except to walk quite a distance from that
part of the house. The FCC test may catch this case, but apparently not
for me, as there are only two wires but that is not the case for other
devices.
 
So phase+neutral could be noisy with respect to protective earth but as
long as it is balanced by an opposite current on protective earth,
radiation should be low.
 
Any other Amateur Radio operators want to weigh in on this?
 
Doug (K4OAP, since 1959)
 

On Tue, 29 Mar 2016 16:13:58 -0500, Ken Javor  wrote:

  Re: [PSES] Commom mode current vs. differential mode current and
LISN Disagree. Westin had it right. A current probe can be used to
isolate either cm or dm current. If at any frequency the signal
amplitude on individual line and neutral conductors are very close,
then all you can say is that at that frequency either cm or dm
predominates, but you can’t say which.  With a LISN, a separate
device must be used. Mark Nave of EMC Services designed a three port
device (connects to each LISN port and to the EMI receiver) trademarked
LISNMATE in the 1980s to isolate common mode, and sometime later he
produced LISNMARK, which isolated DM.  Within the past decade, Ray
Adams while at Fischer Custom Communications packed both functions in
one piece of equipment, which if memory serves was named LISNUP.

EMC Services, Mark Nave’s company, is no longer producing his
products, but I believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261

-
From: Elliott Martinson
Reply-To: Elliott Martinson
Date: Tue, 29 Mar 2016 20:36:18 +
To:
Conversation: [PSES] Commom mode current vs. differential mode current
and LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.
 
Your second point kind of contradicts your first, if it’s trying to
say what I think it is. DM and CM each show up on L, but the same is
true for N. It’s a linear combination of both, so even if L and N are
almost equal, you can’t say anything about the proportion of DM to CM
currents.
 
If they are not equal, then this implies current is travelling back via
the ground conductor and/or energy’s being lost to radiated emissions.
 
What you need is a physical circuit to do the adding/subtracting of the
LISN outputs. (otherwise your 3rd bullet point is correct)
 
Your 4th bullet, well I refer you to the link above.
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com
 

From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Tuesday, March 29, 2016 1:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Commom mode current vs. differential mode current and LISN

Please correct me, if I am wrong (that happens quite often …):

·    Let one wire (L) pass through a current clamp, and you
measure the combination of current mode and differential mode currents

·    Do the same with wire N. If L and N are (almost)
equal, you either have major part of DM currents or major part of CM
current

·    Let both wire (L and N) pass through a current clamp,
and you measure the only CM current (DM is canceled)

·     When doing conducted emission test by LISN, you
actually get what you get. LISN do not see the difference between CM or
DM. From LISN measurements, you can’t say if noise is CM or DM.

B.regards

Amund

-

This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list. To post a message to the list, send your
e-mail to

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site
at http://product-compliance.oc.ieee.org/ can be used for graphics (in
well-used formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to
unsubscribe)
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For help, send ma

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Ken Javor]

Disagree. Westin had it right. A current probe can be used to isolate either
cm or dm current. If at any frequency the signal amplitude on individual
line and neutral conductors are very close, then all you can say is that at
that frequency either cm or dm predominates, but you can¹t say which.  With
a LISN, a separate device must be used. Mark Nave of EMC Services designed a
three port device (connects to each LISN port and to the EMI receiver)
trademarked LISNMATE in the 1980s to isolate common mode, and sometime later
he produced LISNMARK, which isolated DM.  Within the past decade, Ray Adams
while at Fischer Custom Communications packed both functions in one piece of
equipment, which if memory serves was named LISNUP.

EMC Services, Mark Nave¹s company, is no longer producing his products, but
I believe the FCC product is still available.

Ken Javor
Ph. (256) 650-5261 




From: Elliott Martinson 
Reply-To: Elliott Martinson 
Date: Tue, 29 Mar 2016 20:36:18 +
To: 
Conversation: [PSES] Commom mode current vs. differential mode current and
LISN
Subject: Re: [PSES] Commom mode current vs. differential mode current and
LISN

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.
 
Your second point kind of contradicts your first, if it¹s trying to say what
I think it is. DM and CM each show up on L, but the same is true for N. It¹s
a linear combination of both, so even if L and N are almost equal, you can¹t
say anything about the proportion of DM to CM currents.
 
If they are not equal, then this implies current is travelling back via the
ground conductor and/or energy¹s being lost to radiated emissions.
 
What you need is a physical circuit to do the adding/subtracting of the LISN
outputs. (otherwise your 3rd bullet point is correct)
 
Your 4th bullet, well I refer you to the link above.
 

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com 
 

From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Tuesday, March 29, 2016 1:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Commom mode current vs. differential mode current and LISN
 
Please correct me, if I am wrong (that happens quite often Š):

·Let one wire (L) pass through a current clamp, and you measure the
combination of current mode and differential mode currents

·Do the same with wire N. If L and N are (almost) equal, you either
have major part of DM currents or major part of CM current

·Let both wire (L and N) pass through a current clamp, and you
measure the only CM current (DM is canceled)

· When doing conducted emission test by LISN, you actually get what
you get. LISN do not see the difference between CM or DM. From LISN
measurements, you can¹t say if noise is CM or DM.

B.regards

Amund

 

 

 

 

 

 

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Atta

Re: [PSES] Commom mode current vs. differential mode current and LISN

[Elliott Martinson]

http://www.hottconsultants.com/techtips/CM_vs_DM%20Conducted_Emission.html
This is a great resource for your question.

Your second point kind of contradicts your first, if it’s trying to say what I 
think it is. DM and CM each show up on L, but the same is true for N. It’s a 
linear combination of both, so even if L and N are almost equal, you can’t say 
anything about the proportion of DM to CM currents.

If they are not equal, then this implies current is travelling back via the 
ground conductor and/or energy’s being lost to radiated emissions.

What you need is a physical circuit to do the adding/subtracting of the LISN 
outputs. (otherwise your 3rd bullet point is correct)

Your 4th bullet, well I refer you to the link above.

Elliott Martinson
Product Assurance Specialist I
Electronic Theatre Controls
3031 N PLEASANT VIEW RD
MIDDLETON WI 53562-4809
Work: 608.824.5696 / Cell: 608.209.9897
elliott.martin...@etcconnect.com

From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Tuesday, March 29, 2016 1:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Commom mode current vs. differential mode current and LISN


Please correct me, if I am wrong (that happens quite often …):

• Let one wire (L) pass through a current clamp, and you measure the 
combination of current mode and differential mode currents

• Do the same with wire N. If L and N are (almost) equal, you either 
have major part of DM currents or major part of CM current

• Let both wire (L and N) pass through a current clamp, and you measure 
the only CM current (DM is canceled)

•  When doing conducted emission test by LISN, you actually get what 
you get. LISN do not see the difference between CM or DM. From LISN 
measurements, you can’t say if noise is CM or DM.

B.regards

Amund












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formats), large files, etc.

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[PSES] Commom mode current vs. differential mode current and LISN

[Amund Westin]

Please correct me, if I am wrong (that happens quite often …):

* Let one wire (L) pass through a current clamp, and you measure the 
combination of current mode and differential mode currents

* Do the same with wire N. If L and N are (almost) equal, you either 
have major part of DM currents or major part of CM current

* Let both wire (L and N) pass through a current clamp, and you measure 
the only CM current (DM is canceled)

*  When doing conducted emission test by LISN, you actually get what 
you get. LISN do not see the difference between CM or DM. From LISN 
measurements, you can’t say if noise is CM or DM.

B.regards

Amund

 

 

 

 

 

 


-

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discussion list. To post a message to the list, send your e-mail to 


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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

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[PSES] 61000-3-2

[Mark Schmidt]

Dear group,

The 3-2 standard defines professional  equipment as equipment not intended for 
sale to the general public. I have a product that is not intended for the 
general public but is intended to be connected to a low voltage distribution 
system. It is approximately 300 watts and utilizes multiple DIN rail mounted 
power supplies. Each individual power supply meets the intended specification 
but when all four power supplies are utilized if fails the intended 
specification.
As previously mentioned this device will never be sold to the general public 
and is currently being used in automotive world. This is a measurement device 
that is categorized as measurement equipment so the goal is to meet the 
requirements of IEC61326-1. Now with that said clause 7.2  of the 61326-1 
states that for Class A equipment (which this is) the limits, the measuring 
methods and provisions given in CISPR 11 apply. For Class B equipment, the 
limits, the measuring methods and provisions given in CISPR 11, IEC 61000-3-2 
(or IEC 61000-3-12) and IEC61000-3-3 (or IEC 61000-3-11) apply.
So my interpretation of this standard, since I have a Class A device is that no 
harmonics and flicker are required. Is this correct?

Thank you,
Mark Schmidt

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