Re: Conducted emission measurements
As an industry practice, which method is more commonly used? There would be
some setup time involved for testing tabletop equipment with either method. If
anyone has input on their preference it would be helpful.
Most standards are CISPR based so we must follow the CISPR methods so we have a
common test setup.
Thanks,
Tim Pierce
In a message dated 9/23/2009 8:01:56 AM Pacific Daylight Time,
brian_ku...@lecotc.com writes:
Before the CISPR standards included the level of detail they do now
about the test setup for emissions, we used the ANSI C63.4 standard for test
setup. The latest version I have in our library is the 2001 version which says,
ANSI C63.4:2001, Section 5.2.2 Vertical Conducting Plane
A tabletop device may be measured for AC powerline conducted emissions
without a vertical conducting plane while maintaining the 80 cm EUT elevation
specified in 6.2.1. However, in case of a dispute, ac powerline conducted
emission measurements made on a tabletop device with a vertical, conducting
plane in place shall take precedence.
Also, interesting enough, CISPR11 (EN55011:2006) doesn’t even mention a
vertical plane for conducted emissions testing. I interpreted it as allowing
you to perform conducted emissions on an OATS using the same setup as Radiated
Emissions which would include the 80 cm table and no vertical plane. It would
appear as if the 40cm table is only required for options b) and c) below.
CISPR11:2006, Section 7.1 Measurement of mains terminal disturbance
voltage
The measurement of the mains terminal disturbance voltage may be
carried out:
a) on the radiation test site with the equipment under test
having the same configuration as used during the radiation measurement;
b) above a metal ground plane which shall extend at least 0,5 m
beyond the boundary of the equipment under test and have a minimum size of 2 m
× 2 m; or
c) within a screened room. Either the floor or one wall of the
screened room shall act as the ground plane.
Option a) shall be used where the test site contains a metal ground
plane.
In options b) and c) the test unit, if non-floor-standing, shall be
placed 0,4 m from the ground plane.
Floorstanding test units shall be placed on the ground plane, the
point(s) of contact being insulated from the ground plane but otherwise
consistent with normal use. All test units shall be at least 0,8 m from any
other metal surface.
Does EN55022 allow conducted emissions to be performed on an OATS
without the vertical plane and with an 80 cm table? It sounds like it does as
an optional configuration (I’m not an expert on EN55022).
I would interpret a Semi-Anechoic chamber the same as an OATS.
The Other Brian
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of
Spencer, David H
Sent: Wednesday, September 23, 2009 7:50 AM
To: Wan Juang Foo; emcp...@aol.com; emc-p...@ieee.org
Subject: RE: Conducted emission measurements
Tim,
From EN55022:2006 +A1: 2007
Section 9.5.2 Tabletop equipment arrangement
2) "...(for example on an open area test site (OATS) or in a
screened enclosure). The EUT shall be placed on a non-conductive table such
that it is 0,4m above the horizontal ground reference plane."
Regards,
David Spencer
EMC Engineer
Xerox Corp.
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of
Wan Juang Foo
Sent: Wednesday, September 23, 2009 1:46 AM
To: emcp...@aol.com; emc-p...@ieee.org
Cc: Wan Juang Foo
Subject: Re: Conducted emission measurements
Hello Tim,
I may be missing. Is there such a 40 cm height? Here is my 5 ¢
worth.
These are some of the the special provision for conducted
emission testing:
To meet EN 55011, I suppose since 1999?? the measurement may be
carried out:
- on the radiated emission test site (same EUT configuration)
- above a metal ground plane which shall extend at least
50 cm beyond the boundary of the equipment under test
and have a minimum size of 2m x 2m
- within a screened room; either the floor or one wall of
the screened room shall act as the vertical ground plane
.. CISPR 22 since (1993) and Amendme
RE: Conducted emission measurements
Brian,
Regarding EN55022 Conducted Emissions on OATS, the table height should be 40cm
not 80cm. This is an alternate test method per Section 9.5.2-2 and Figure 7.
All other conductive surfaces should be at least 80cm from the EUT and the
cable bundles should maintain the 40cm separation from the GRP.
Regards,
Steve O'Steen
Director, EMC
Advanced Compliance Solutions, Inc.
sost...@acstestlab.com <mailto:sost...@acstestlab.com>
770-831-8048 ext. 210
www.acstestlab.com <http://www.acstestlab.com>
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From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Kunde, Brian
Sent: Wednesday, September 23, 2009 11:01 AM
To: Spencer, David H; Wan Juang Foo; emcp...@aol.com; emc-p...@ieee.org
Subject: RE: Conducted emission measurements
Before the CISPR standards included the level of detail they do now about the
test setup for emissions, we used the ANSI C63.4 standard for test setup. The
latest version I have in our library is the 2001 version which says,
ANSI C63.4:2001, Section 5.2.2 Vertical Conducting Plane
A tabletop device may be measured for AC powerline conducted emissions without
a vertical conducting plane while maintaining the 80 cm EUT elevation
specified in 6.2.1. However, in case of a dispute, ac powerline conducted
emission measurements made on a tabletop device with a vertical, conducting
plane in place shall take precedence.
Also, interesting enough, CISPR11 (EN55011:2006) doesn’t even mention a
vertical plane for conducted emissions testing. I interpreted it as allowing
you to perform conducted emissions on an OATS using the same setup as Radiated
Emissions which would include the 80 cm table and no vertical plane. It would
appear as if the 40cm table is only required for options b) and c) below.
CISPR11:2006, Section 7.1 Measurement of mains terminal disturbance voltage
The measurement of the mains terminal disturbance voltage may be carried out:
a) on the radiation test site with the equipment under test having the
same configuration as used during the radiation measurement;
b) above a metal ground plane which shall extend at least 0,5 m beyond
the boundary of the equipment under test and have a minimum size of 2 m × 2
m; or
c) within a screened room. Either the floor or one wall of the screened
room shall act as the ground plane.
Option a) shall be used where the test site contains a metal ground plane.
In options b) and c) the test unit, if non-floor-standing, shall be placed 0,4
m from the ground plane.
Floorstanding test units shall be placed on the ground plane, the point(s) of
contact being insulated from the ground plane but otherwise consistent with
normal use. All test units shall be at least 0,8 m from any other metal
surface.
Does EN55022 allow conducted emissions to be performed on an OATS without the
vertical plane and with an 80 cm table? It sounds like it does as an optional
configuration (I’m not an expert on EN55022).
I would interpret a Semi-Anechoic chamber the same as an OATS.
The Other Brian
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Spencer, David
H
Sent: Wednesday, September 23, 2009 7:50 AM
To: Wan Juang Foo; emcp...@aol.com; emc-p...@ieee.org
Subject: RE: Conducted emission measurements
Tim,
>From EN55022:2006 +A1: 2007
Section 9.5.2 Tabletop equipment arrangement
2) "...(for example on an open area test site (OATS) or in a screened
enclosure). The EUT shall be placed on a non-conductive table such that it is
0,4m above the horizontal ground reference plane."
Regards,
David Spencer
EMC Engineer
Xerox Corp.
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Wan
Juang Foo
Sent: Wednesday, September 23, 2009 1:46 AM
To: emcp...@aol.com; emc-p...@ieee.org
Cc: Wan Juang Foo
Subject: Re: Conducted emission measurements
Hello Tim,
I may be missing. Is there such a 40 cm height? Here is my 5 ¢ worth.
These are some of the the special provision for conducted emission
testing:
To meet EN 55011, I suppose since 1999?? the measurement may be carried
out:
- on t
RE: Conducted emission measurements
Before the CISPR standards included the level of detail they do now about the
test setup for emissions, we used the ANSI C63.4 standard for test setup. The
latest version I have in our library is the 2001 version which says,
ANSI C63.4:2001, Section 5.2.2 Vertical Conducting Plane
A tabletop device may be measured for AC powerline conducted emissions without
a vertical conducting plane while maintaining the 80 cm EUT elevation
specified in 6.2.1. However, in case of a dispute, ac powerline conducted
emission measurements made on a tabletop device with a vertical, conducting
plane in place shall take precedence.
Also, interesting enough, CISPR11 (EN55011:2006) doesn’t even mention a
vertical plane for conducted emissions testing. I interpreted it as allowing
you to perform conducted emissions on an OATS using the same setup as Radiated
Emissions which would include the 80 cm table and no vertical plane. It would
appear as if the 40cm table is only required for options b) and c) below.
CISPR11:2006, Section 7.1 Measurement of mains terminal disturbance voltage
The measurement of the mains terminal disturbance voltage may be carried out:
a) on the radiation test site with the equipment under test having the
same configuration as used during the radiation measurement;
b) above a metal ground plane which shall extend at least 0,5 m beyond
the boundary of the equipment under test and have a minimum size of 2 m × 2
m; or
c) within a screened room. Either the floor or one wall of the screened
room shall act as the ground plane.
Option a) shall be used where the test site contains a metal ground plane.
In options b) and c) the test unit, if non-floor-standing, shall be placed 0,4
m from the ground plane.
Floorstanding test units shall be placed on the ground plane, the point(s) of
contact being insulated from the ground plane but otherwise consistent with
normal use. All test units shall be at least 0,8 m from any other metal
surface.
Does EN55022 allow conducted emissions to be performed on an OATS without the
vertical plane and with an 80 cm table? It sounds like it does as an optional
configuration (I’m not an expert on EN55022).
I would interpret a Semi-Anechoic chamber the same as an OATS.
The Other Brian
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Spencer, David
H
Sent: Wednesday, September 23, 2009 7:50 AM
To: Wan Juang Foo; emcp...@aol.com; emc-p...@ieee.org
Subject: RE: Conducted emission measurements
Tim,
>From EN55022:2006 +A1: 2007
Section 9.5.2 Tabletop equipment arrangement
2) "...(for example on an open area test site (OATS) or in a screened
enclosure). The EUT shall be placed on a non-conductive table such that it is
0,4m above the horizontal ground reference plane."
Regards,
David Spencer
EMC Engineer
Xerox Corp.
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Wan
Juang Foo
Sent: Wednesday, September 23, 2009 1:46 AM
To: emcp...@aol.com; emc-p...@ieee.org
Cc: Wan Juang Foo
Subject: Re: Conducted emission measurements
Hello Tim,
I may be missing. Is there such a 40 cm height? Here is my 5 ¢ worth.
These are some of the the special provision for conducted emission
testing:
To meet EN 55011, I suppose since 1999?? the measurement may be carried
out:
- on the radiated emission test site (same EUT configuration)
- above a metal ground plane which shall extend at least
50 cm beyond the boundary of the equipment under test
and have a minimum size of 2m x 2m
- within a screened room; either the floor or one wall of
the screened room shall act as the vertical ground plane
.. CISPR 22 since (1993) and Amendment 1 (1995)
Table- top EUTis to be placed 40 cm from a vertical metal reference
plane
(e.g. a wall of a screened room/enclosure)
"The EUT, where intended for table-top use, shall be placed 0,4 m from a
vertical metal reference plane of at least 2 m by 2 m and shall be kept at
least 0,8 m from any other metal surface or other ground-plane not being part
of the EUT. If the measurement. is made in a screened enclosure, the distance
of 0,4 m may be referred to one of the walls of the enclosure."
Floor- standing EUT on a horizontal metal ground- plane, not in metallic
contact with the ground- plane. Metal floor of a screened room may replace the
reference ground- plane
best regards,
Tim Foo
Expert Witness, EMC and Product Safety
ECE, School of Engineering,
http://www.np.edu.sg/ece/ DID: +65 6460 6143
Ngee Ann Polytechnic,
535 Clementi Road, Fax: +65 6467 1730
Singapore 599489
emc
Re: Conducted emission measurements
What is the rationale behind a vertical conducting surface for conducted emissions? Ken Javor Phone: (256) 650-5261 From: Wan Juang Foo List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wed, 23 Sep 2009 13:46:27 +0800 To: , Cc: Wan Juang Foo Subject: Re: Conducted emission measurements Hello Tim, I may be missing. Is there such a 40 cm height? Here is my 5 ¢ worth. These are some of the the special provision for conducted emission testing: To meet EN 55011, I suppose since 1999?? the measurement may be carried out: - on the radiated emission test site (same EUT configuration) - above a metal ground plane which shall extend at least 50 cm beyond the boundary of the equipment under test and have a minimum size of 2m x 2m - within a screened room; either the floor or one wall of the screened room shall act as the vertical ground plane .. CISPR 22 since (1993) and Amendment 1 (1995) Table- top EUTis to be placed 40 cm from a vertical metal reference plane (e.g. a wall of a screened room/enclosure) "The EUT, where intended for table-top use, shall be placed 0,4 m from a vertical metal reference plane of at least 2 m by 2 m and shall be kept at least 0,8 m from any other metal surface or other ground-plane not being part of the EUT. If the measurement. is made in a screened enclosure, the distance of 0,4 m may be referred to one of the walls of the enclosure." Floor- standing EUT on a horizontal metal ground- plane, not in metallic contact with the ground- plane. Metal floor of a screened room may replace the reference ground- plane best regards, Tim Foo Expert Witness, EMC and Product Safety ECE, School of Engineering, http://www.np.edu.sg/ece/ DID: +65 6460 6143 Ngee Ann Polytechnic, 535 Clementi Road, Fax: +65 6467 1730 Singapore 599489 emc-p...@ieee.org wrote on 23/09/2009 06:06:05 AM: > Hello Group, > > I have a question about the conducted emission measurements > performed in a semi-anechoic chamber. > > CISPR 22 requires the use of a vertical ground plane when testing > tabletop EUTs, unless you mount your EUT on a non-conductive table > 40cm above the horizontal ground plane (instead of the traditional 80cm) > > I did not find a requirement for a vertical ground plane when > testing floorstanding equipment. If one opts to use the alternative > method of not using the vertical ground plane, can floorstanding > equipment also be tested without the vertical ground plane? The > horizontal ground plane is always present since that is the chamber floor. > > What are most labs using? We have the option of making a removable > vertical ground plane "wall" or mounting the equipment on a 40cm table. > > Thanks, > Tim Pierce > - NOTICE: This message may contain privileged/confidential information. If you are not the intended recipient of this email, please delete it immediately and notify the sender . - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas Mike Cantwell For policy questions, send mail to: Jim Bacher David Heald
Re: Conducted emission measurements
In message <78eac2d97114034eb62aaa10fcc251060a71d...@usa7061ms01.na.xerox.net>, dated Wed, 23 Sep 2009, "Spencer, David H" writes: >From EN55022:2006 +A1: 2007 > >Section 9.5.2 Tabletop equipment arrangement > > >2) "...(for example on an open area test site (OATS) or in a >screened enclosure). The EUT shall be placed on a non-conductive table >such that it is 0,4m above the horizontal ground reference plane." > Citing the standard, with date and with applicable amendment. Citing the clause (IEC-speak for a numbered division) and the item within it. Oh, if only everyone would do that! Have an award! (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas Mike Cantwell For policy questions, send mail to: Jim Bacher: David Heald:
RE: Conducted emission measurements
Tim,
>From EN55022:2006 +A1: 2007
Section 9.5.2 Tabletop equipment arrangement
2) "...(for example on an open area test site (OATS) or in a screened
enclosure). The EUT shall be placed on a non-conductive table such that it is
0,4m above the horizontal ground reference plane."
Regards,
David Spencer
EMC Engineer
Xerox Corp.
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Wan
Juang Foo
Sent: Wednesday, September 23, 2009 1:46 AM
To: emcp...@aol.com; emc-p...@ieee.org
Cc: Wan Juang Foo
Subject: Re: Conducted emission measurements
Hello Tim,
I may be missing. Is there such a 40 cm height? Here is my 5 ¢ worth.
These are some of the the special provision for conducted emission
testing:
To meet EN 55011, I suppose since 1999?? the measurement may be
carried out:
- on the radiated emission test site (same EUT
configuration)
- above a metal ground plane which shall extend at least
50 cm beyond the boundary of the equipment under test
and have a minimum size of 2m x 2m
- within a screened room; either the floor or one wall
of
the screened room shall act as the vertical ground plane
.. CISPR 22 since (1993) and Amendment 1 (1995)
Table- top EUTis to be placed 40 cm from a vertical
metal reference plane
(e.g. a wall of a screened room/enclosure)
"The EUT, where intended for table-top use, shall be
placed 0,4 m from a
vertical metal reference plane of at least 2 m by 2 m and shall be kept at
least 0,8 m from any other metal surface or other ground-plane not being part
of the EUT. If the measurement. is made in a screened enclosure, the distance
of 0,4 m may be referred to one of the walls of the enclosure."
Floor- standing EUT on a horizontal metal ground-
plane, not in metallic
contact with the ground- plane. Metal floor of a screened room may replace the
reference ground- plane
best regards,
Tim Foo
Expert Witness, EMC and Product Safety
ECE, School of Engineering,
http://www.np.edu.sg/ece/ DID: +65 6460 6143
Ngee Ann Polytechnic,
535 Clementi Road, Fax: +65 6467 1730
Singapore 599489
emc-p...@ieee.org wrote on 23/09/2009 06:06:05 AM:
> Hello Group,
>
> I have a question about the conducted emission measurements
> performed in a semi-anechoic chamber.
>
> CISPR 22 requires the use of a vertical ground plane when testing
> tabletop EUTs, unless you mount your EUT on a non-conductive table
> 40cm above the horizontal ground plane (instead of the traditional
80cm)
>
> I did not find a requirement for a vertical ground plane when
> testing floorstanding equipment. If one opts to use the alternative
> method of not using the vertical ground plane, can floorstanding
> equipment also be tested without the vertical ground plane? The
> horizontal ground plane is always present since that is the chamber
floor.
>
> What are most labs using? We have the option of making a removable
> vertical ground plane "wall" or mounting the equipment on a 40cm
table.
>
> Thanks,
> Tim Pierce
> -
NOTICE:
This message may contain privileged/confidential information. If you
are not
the intended recipient of this email, please delete it immediately and notify
the sender .
-
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Graphics (in well-used formats), large files, etc. can be posted to that URL.
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Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
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Mike Cantwell
For policy questions, send mail to:
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David Heald
Re: Conducted emission measurements
Hello Tim, I may be missing. Is there such a 40 cm height? Here is my 5 ¢ worth. These are some of the the special provision for conducted emission testing: To meet EN 55011, I suppose since 1999?? the measurement may be carried out: - on the radiated emission test site (same EUT configuration) - above a metal ground plane which shall extend at least 50 cm beyond the boundary of the equipment under test and have a minimum size of 2m x 2m - within a screened room; either the floor or one wall of the screened room shall act as the vertical ground plane .. CISPR 22 since (1993) and Amendment 1 (1995) Table- top EUTis to be placed 40 cm from a vertical metal reference plane (e.g. a wall of a screened room/enclosure) "The EUT, where intended for table-top use, shall be placed 0,4 m from a vertical metal reference plane of at least 2 m by 2 m and shall be kept at least 0,8 m from any other metal surface or other ground-plane not being part of the EUT. If the measurement. is made in a screened enclosure, the distance of 0,4 m may be referred to one of the walls of the enclosure." Floor- standing EUT on a horizontal metal ground- plane, not in metallic contact with the ground- plane. Metal floor of a screened room may replace the reference ground- plane best regards, Tim Foo Expert Witness, EMC and Product Safety ECE, School of Engineering, http://www.np.edu.sg/ece/ DID: +65 6460 6143 Ngee Ann Polytechnic, 535 Clementi Road, Fax: +65 6467 1730 Singapore 599489 emc-p...@ieee.org wrote on 23/09/2009 06:06:05 AM: > Hello Group, > > I have a question about the conducted emission measurements > performed in a semi-anechoic chamber. > > CISPR 22 requires the use of a vertical ground plane when testing > tabletop EUTs, unless you mount your EUT on a non-conductive table > 40cm above the horizontal ground plane (instead of the traditional 80cm) > > I did not find a requirement for a vertical ground plane when > testing floorstanding equipment. If one opts to use the alternative > method of not using the vertical ground plane, can floorstanding > equipment also be tested without the vertical ground plane? The > horizontal ground plane is always present since that is the chamber floor. > > What are most labs using? We have the option of making a removable > vertical ground plane "wall" or mounting the equipment on a 40cm table. > > Thanks, > Tim Pierce > - NOTICE: This message may contain privileged/confidential information. If you are not the intended recipient of this email, please delete it immediately and notify the sender .
RE: Conducted emission measurements
This was one of the reasons we designed and built our own analogue transistors load banks. The ones available on the market are often noisy and not suitable for EMC emissions measurements. At least, that's been my experience. A resistor bank has the advantage of simplicity, but the disadvantage of lack of adjustability. A transistor load bank can be designed to be continuously variable and can present a constant-resistance, constant-current or constant-power load to the EUT. == Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc. _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of McInturff Gary Sent: Thursday, May 18, 2006 9:03 AM To: Price, Ed; emc-p...@ieee.org Subject: RE: Conducted emission measurements Agree with ED, the las time I used and electronic load it was terrible noisey in-and-of-itself. Too noisey for emissions tests. As lab equipment – at the time – it didn’t hgave any FCC emissions testing – and so I doubt it addressed this area at all. Maybe better these days but I would be skeptical until I tested a sample. Gary - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conducted emission measurements
Hi David, A couple of possibilities: - You have an increase in RF currents flowing from the power supply, through the electronic load, to it's power source (regardless whether the electronic load is grounded). Note: EN55022:1998, clause 9.2.e says that other power cords from the system (in this case, your electronic load) need to be connected to their own artificial mains network. - The volume of the electronic load is much bigger than the resistive load, and has more capacitance to the ground plane of the test setup. - Emissions testing is very sensitive to wire length and position. We normally do EMC testing with a resistive load, using wires as short as practical. A customer once reported a difference in readings when he tested our power supply with a resistive load. When I asked for a picture of the test setup, I saw his resistive load and hookup wire formed a loop about 2 feet in diameter. When I re-created his resistive load from the picture, I saw an increase in my own noise measurements of 10dB. Pat Lawler EMC Engineer Condor DC Power Supplies emc-p...@ieee.org wrote on 05/18/2006 08:08:46 AM: > We measured conducted emissions of a switched mode ac-dc power supply > and found that emissions are much higher when using an electronic load > compared to a resistive load. Can somebody explain why this is? > Thanks, > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Conducted emission measurements
I suggest that if one is interested only in the emissions from the EUT, then a stack of resistors is the easiest way to build a suitable load. If one is interested in functional interaction between power supply and an active load (perhaps DC-DC converter) then okay, but how would you distinguish noise from the load from noise from the EUT? There are so many different types of passive and active loads which power supply could support, where would one start and finish? I think it's very similar why trying to determine how much current THD an EUT produces versus how much is produced by the voltage distortion on the electricity supply. Unless you can determine that a transistorized load bank is "quiet" and doesn't interact with the power supply under test, then I propose that a passive, resistive load is better when measuring conducted or radiated emissions or immunity on an inverter or a converter product. == Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc., _ Dave: I would imagine that the electronic load is itself a noise source. You are likely seeing the noise of the load, filtered and isolated by the power supply. Further, the power supply might not like the noise of the electronic load, and respond with even more power supply noise. Also, the electronic load may be providing a common mode path for power supply output noise. I generally avoid electronic loads, but it could be argued that a digital load looks a lot more realistic than a stack of non-inductive resistors. You should know what happens when your power supply is feeding real electronics as well as a passive load. Regards, Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty - - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Conducted emission measurements
Agree with ED, the las time I used and electronic load it was terrible noisey in-and-of-itself. Too noisey for emissions tests. As lab equipment – at the time – it didn’t hgave any FCC emissions testing – and so I doubt it addressed this area at all. Maybe better these days but I would be skeptical until I tested a sample. Gary _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Price, Ed Sent: Thursday, May 18, 2006 8:36 AM To: emc-p...@ieee.org Subject: RE: Conducted emission measurements > -Original Message- > From: David Gelfand [mailto:david.gelf...@mitectelecom.com] > Sent: Thursday, May 18, 2006 8:09 AM > To: emc-p...@ieee.org > Subject: Conducted emission measurements > > We measured conducted emissions of a switched mode ac-dc > power supply and found that emissions are much higher when > using an electronic load compared to a resistive load. Can > somebody explain why this is? > > Thanks, > > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 Dave: I would imagine that the electronic load is itself a noise source. You are likely seeing the noise of the load, filtered and isolated by the power supply. Further, the power supply might not like the noise of the electronic load, and respond with even more power supply noise. Also, the electronic load may be providing a common mode path for power supply output noise. I generally avoid electronic loads, but it could be argued that a digital load looks a lot more realistic than a stack of non-inductive resistors. You should know what happens when your power supply is feeding real electronics as well as a passive load. Regards, Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Conducted emission measurements
Good People, Conflict of Interest Notice: my employer makes component SMPS. The control loop for an analog load can also cause problems if the loop response time "beats" against a fundamental of the SMPS for that particular load setting. That is why my employer has a requirement to "sweep" the output load to detect any control instabilities. As for failure of the conducted emissions test, the end unit should be operated in a "normal" manner. That is, if the power supply has problems with conducted emissions in your box, then your box may need another power supply (and do not add "significant" capacitance to the output without consulting the SMPS mfr). luck, Brian > -Original Message- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Ralph > McDiarmid > Sent: Thursday, May 18, 2006 8:24 AM > To: emc-p...@ieee.org > Subject: RE: Conducted emission measurements > > > We have discovered that some commercially available electronic loads > have conducted emissions of their own and these currents find > there way > into the device-under-test. > > Consider using either resistive load or an analogue controlled > transistor load bank. (no switching circuits or oscillators inside). > We built our own for all DVT testing including EMC. > > == > > Ralph McDiarmid, ASc > Compliance Engineering Group > Xantrex Technology Inc. > > > -Original Message- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of David > Gelfand > Sent: Thursday, May 18, 2006 8:09 AM > To: emc-p...@ieee.org > Subject: Conducted emission measurements > > We measured conducted emissions of a switched mode ac-dc power supply > and found that emissions are much higher when using an electronic load > compared to a resistive load. Can somebody explain why this is? > > Thanks, > > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Conducted emission measurements
> -Original Message- > From: David Gelfand [mailto:david.gelf...@mitectelecom.com] > Sent: Thursday, May 18, 2006 8:09 AM > To: emc-p...@ieee.org > Subject: Conducted emission measurements > > We measured conducted emissions of a switched mode ac-dc > power supply and found that emissions are much higher when > using an electronic load compared to a resistive load. Can > somebody explain why this is? > > Thanks, > > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 Dave: I would imagine that the electronic load is itself a noise source. You are likely seeing the noise of the load, filtered and isolated by the power supply. Further, the power supply might not like the noise of the electronic load, and respond with even more power supply noise. Also, the electronic load may be providing a common mode path for power supply output noise. I generally avoid electronic loads, but it could be argued that a digital load looks a lot more realistic than a stack of non-inductive resistors. You should know what happens when your power supply is feeding real electronics as well as a passive load. Regards, Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Conducted emission measurements
We have discovered that some commercially available electronic loads have conducted emissions of their own and these currents find there way into the device-under-test. Consider using either resistive load or an analogue controlled transistor load bank. (no switching circuits or oscillators inside). We built our own for all DVT testing including EMC. == Ralph McDiarmid, ASc Compliance Engineering Group Xantrex Technology Inc. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of David Gelfand Sent: Thursday, May 18, 2006 8:09 AM To: emc-p...@ieee.org Subject: Conducted emission measurements We measured conducted emissions of a switched mode ac-dc power supply and found that emissions are much higher when using an electronic load compared to a resistive load. Can somebody explain why this is? Thanks, David. David Gelfand, P.E. Product Integrity Engineer Mitec Telecom Inc 9000 Trans-Canada Highway Montreal QC H9R 5Z8 Canada 514 694 9000 x2262 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
