Re: Labelling requirements components

[peter merguerian]

Andre,

German deviations to 950, requires the service markings and instructions to be
in German also.

Peter

 Andre Boons  wrote: 



Hi,

If a manufacturer is required to put information on the label of his 
product, it must be in a language that is acceptable for the user in the 
country where the product is put on the market.

If the above product consists of a certain part that can be replaced during 
service operations locally and there are special precautions to be taken 
care of when replacements takes place, should the label on that part also be 
in the language of the country where the final product is marketed.
An example could be a CRT of a VDU that needs replacement by exactly the 
same type.

Regards,
Andre




_




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IEC 60950:1999 - Australian Deviations

[Kevin Richardson]

All,

Thought I should let the group know that IECEE CB Scheme accredited test
labs can now officially issue CB Certificates and test reports to IEC
60950:1999 (3rd Edition) including Australian deviations.  Previously, CB
Certificates and reports could only officially include Australian deviations
to the 2nd Edition (IEC 950:1991).

Australian deviations to the 3rd Edition were never included in the CB
Bulletin due to and oversight (too complicated to explain).  This was
recently corrected (some time shortly after 20 Dec 02).  The Australian
deviations to the 3rd Edition are now listed in the CB Bulletin area of the
IECEE web site in the "TEMPORARY" file and I understand will be included in
the next published CB Bulletin.

The same is true for Australian deviations to IEC 60065:1998 (6th Edition).


Best regards,
Kevin Richardson

Stanimore Pty Limited
Compliance Advice & Solutions for Technology
(Legislation/Regulations/Standards/Australian Agent Services)
Ph:   02-4329-4070   (Int'l: +61-2-4329-4070)
Fax:  02-4328-5639   (Int'l: +61-2-4328-5639)
Mobile:  04-1224-1620   (Int'l: +61-4-1224-1620)
Email:kevin.richard...@ieee.org

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RE: rj45 with integrated magnetics..

[neve...@attbi.com]

You can find all sorts of different transformer configurations. The magnetics 
vendors have technical stuff that often knows what is good and in which 
application, yet they also sell what they know isn't technically very good.
The 
reason is that oftentimes customers require a specific configuration, and if 
they want to get business they do what customers ask them.

If you need guidance in selecting a part from a magnetics company, ask to
speak 
with their lead design enginieers, and only after that discuss it with the 
sales guys.

Neven
> The magnetics are made up of both a 1 to 1 isolation xformer and a cm choke.
I 
> just stared at a schematic and I don't know if its an error, a single part
or 
> generic, but for this one part the common mode choke was on the cable side
for 
> the TX lines and on the IC side for the RX lines. I have never noticed that 
> before. I'll be looking at some other parts now that you have my interest 
> piqued.
> Gary
> -Original Message-
> From: Muhammad Sagarwala [mailto:msa...@force10networks.com]
> Sent: Monday, February 03, 2003 9:00 AM
> To: emc-p...@majordomo.ieee.org
> Subject: rj45 with integrated magnetics..
> 
> 
> 
> Here is a question for you Gurus.. 
> 
> I was looked at a few different rj45 with integrated magnetics.  While all
of 
> them were different in some respect, I found two major categories - one with 
> common mode choke on the chip (IC) side while others with common mode choke
on 
> the cable side.  My question would be "why would one want to use a connector
> with common mode choke on the chip side vs connector with common mode choke
on 
> the cable side??? I wanted to know specific scenario where  a person would 
> prefer one over the other."  
> 
> Here I would like to add that most of the problems I have seen in my short 
> career are due to common mode noise making its way to the cable.  
> 
> Also, I would appreciate if someone could point me to a document where I
could 
> find rules/factors to consider while selecting a jack with integrated
magnetics 
> .
> 
> Muhammad 
> 
> 


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RE: rj45 with integrated magnetics..

[neve...@attbi.com]

You can find all sorts of different transformer configurations. The magnetics 
vendors have technical stuff that often knows what is good and in which 
application, yet they also sell what they know isn't technically very good.
The 
reason is that oftentimes customers require a specific configuration, and if 
they need to get business they do what customers ask them.

If you need guidance in selecting a part from a magnetics company, ask to
speak 
with their lead design enginieers, and only after that discuss it with the 
sales guys.

Neven
> The magnetics are made up of both a 1 to 1 isolation xformer and a cm choke.
I 
> just stared at a schematic and I don't know if its an error, a single part
or 
> generic, but for this one part the common mode choke was on the cable side
for 
> the TX lines and on the IC side for the RX lines. I have never noticed that 
> before. I'll be looking at some other parts now that you have my interest 
> piqued.
> Gary
> -Original Message-
> From: Muhammad Sagarwala [mailto:msa...@force10networks.com]
> Sent: Monday, February 03, 2003 9:00 AM
> To: emc-p...@majordomo.ieee.org
> Subject: rj45 with integrated magnetics..
> 
> 
> 
> Here is a question for you Gurus.. 
> 
> I was looked at a few different rj45 with integrated magnetics.  While all
of 
> them were different in some respect, I found two major categories - one with 
> common mode choke on the chip (IC) side while others with common mode choke
on 
> the cable side.  My question would be "why would one want to use a connector
> with common mode choke on the chip side vs connector with common mode choke
on 
> the cable side??? I wanted to know specific scenario where  a person would 
> prefer one over the other."  
> 
> Here I would like to add that most of the problems I have seen in my short 
> career are due to common mode noise making its way to the cable.  
> 
> Also, I would appreciate if someone could point me to a document where I
could 
> find rules/factors to consider while selecting a jack with integrated
magnetics 
> .
> 
> Muhammad 
> 
> 


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Labelling requirements components

[Andre Boons]

Hi,

If a manufacturer is required to put information on the label of his 
product, it must be in a language that is acceptable for the user in the 
country where the product is put on the market.

If the above product consists of a certain part that can be replaced during 
service operations locally and there are special precautions to be taken 
care of when replacements takes place, should the label on that part also be 
in the language of the country where the final product is marketed.
An example could be a CRT of a VDU that needs replacement by exactly the 
same type.

Regards,
Andre




_




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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tr ipping Dring Fault Tests)

[drcuthbert]

What is needed is the I squared t rating of the breaker. Then the (I^2)(t)
rating of the PCB. Then you know if the PCB can take it. 

   Dave Cuthbert


From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Monday, February 03, 2003 4:15 PM
To: emc-p...@majordomo.ieee.org
Subject: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)



I read in !emc-pstc that cnew...@xycom.com wrote (in <85256CC2.005F2DA4.
0...@notes.fw.xycom.com>) about 'EN60950 protective conductor test (was
Re: Circuit Breaker  Tripping Dring Fault Tests)' on Mon, 3 Feb
2003:

>My UL guy tells me that I should expect the typical service type CB to be
rated
>up to  + 10%.  So it appears that  I need to concern myself with a burst of
>current
>up to approximately 22 amps for the 20 amp AC circuit that my product is
being
>evaluated for.

Until it trips, your CB lets through the **whole 200 A**. The trip
current is practically irrelevant in this test; what matters is the trip
TIME. The board trace may stand 200 A for 50 ms but not for 100 ms.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk

Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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RE: red tape

[Price, Ed]

>-Original Message-
>From: Ravinder Ajmani [mailto:ajm...@us.ibm.com]
>Sent: Monday, February 03, 2003 12:55 PM
>To: emc-p...@majordomo.ieee.org
>Subject: Re: red tape
>
>
>Red Tape is a very common term used for describing the bureaucracy of
>Government of India (perhaps a legacy from British).  Delays 
>and inaction
>by Indian bureaucracy have often been blamed to the Red Tape in the
>government offices (which signifies a cloth ribbon tied around a file
>folder to hold the papers in place).  One result of the 
>criticism was that
>the red tape was subsequently replaced with a white tape.  
>Although it is
>anybody's guess, if this actually improved the working at the 
>government
>offices.
>
>Regards, Ravinder
>PCB Development and Design Department
>


But DUCT TAPE is your friend, regardless of color!

Ed

Ed Price
ed.pr...@cubic.com
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA  USA
858-505-2780  (Voice)
858-505-1583  (Fax)
Military & Avionics EMC Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis


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CE marking and additional information requirements

[Georgerian, Richard]

Greetings All, 

Variants of the CE marking question have been raised before, so here's another
one or two. 

Does the CE mark have to be located near other information such has company
name/trade mark, product name/model number or electrical ratings? Or can it
stand alone without such information?

Reading the LVD, EMC and the CE Directives, they mention affixing the CE Mark,
but does not state any additional information that needs to be located near
the CE mark. Also, I checked past postings on the CE Mark and did not have any
luck finding if these questions were answered.

Thanks in-advance. 

Richard Georgerian 
Compliance Engineer 
Carrier Access Corporation 
5395 Pearl Parkway 
Boulder, CO 80301 
USA 

Tele: 303-218-5748  Fax: 303-218-5503  
mailto:rgeorger...@carrieraccess.com 



*
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EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[John Woodgate]

I read in !emc-pstc that cnew...@xycom.com wrote (in <85256CC2.005F2DA4.
0...@notes.fw.xycom.com>) about 'EN60950 protective conductor test (was
Re: Circuit Breaker  Tripping Dring Fault Tests)' on Mon, 3 Feb
2003:

>My UL guy tells me that I should expect the typical service type CB to be
rated
>up to  + 10%.  So it appears that  I need to concern myself with a burst of
>current
>up to approximately 22 amps for the 20 amp AC circuit that my product is being
>evaluated for.

Until it trips, your CB lets through the **whole 200 A**. The trip
current is practically irrelevant in this test; what matters is the trip
TIME. The board trace may stand 200 A for 50 ms but not for 100 ms.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Re: CE marking and additional information requirements

[John Woodgate]

I read in !emc-pstc that Georgerian, Richard  wrote (in ) about 'CE marking and additional information requirements'
on Mon, 3 Feb 2003:
>Does the CE mark have to be located near other information such has
company 
>name/trade mark, product name/model number or electrical ratings? Or can
it 
>stand alone without such information?

It can stand alone.
>
>Reading the LVD, EMC and the CE Directives, they mention affixing the CE 
>Mark, but does not state any additional information that needs to be
located 
>near the CE mark. Also, I checked past postings on the CE Mark and did
not 
>have any luck finding if these questions were answered.

There is now no requirement for any additional information to accompany
the CE mark under the Directives you cite. But other Directives may
require more information.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Re: rj45 with integrated magnetics..

[John Woodgate]

I read in !emc-pstc that neve...@attbi.com wrote (in <200302032124.h13LO
ik28...@orion2.ieee.org>) about 'rj45 with integrated magnetics..' on
Mon, 3 Feb 2003:
>If you can get access to it, see Broadcom application note "10/100 and Gbit 
>PHYs, EMC Design Guidelines". You'd need a password from your Broadcom rep to 
>get it.

Why would a supplier make its product support information hard to get?
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Medium voltage, high frequency

[Nick Williams]

I have a client with an application which involves the application of 
between 2 and 6kV at frequencies in the range 10 - 100kHz and power 
in the low kW range.

I'm afraid I'm not allowed to tell you exactly what this equipment 
does, but this is equipment for which there appear to be no specific 
standards.

Can anyone point me at some guidance material which might help me to 
better understand any particular additional risks associated with 
electricity at these voltages and frequencies?

The sort of thing I am interested in is any guidance on the medium 
and long term performance of insulating materials and any special 
risks from electric shock at these frequencies. I'm not so much 
looking for standards and formal requirements as for the benefit of 
real technical experience in this sort of application.

Any help gratefully received.

Regards

Nick.


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Re: red tape and European voltage harmonization

[John Woodgate]

I read in !emc-pstc that Ted Rook  wrote (in
) about 'red tape and European voltage
harmonization' on Mon, 3 Feb 2003:

>In the UK your equipment will be connected to 240V and will be expected to
work 
>to specification. 
>The upper limit should be 230 + 10% = 253V but don't hold your breath.

AIUI, the 253 V upper limit WILL be held. Certainly here at Rayleigh the
voltage sometimes gets close to 253 V, but not over.

> Do UK 
>labs will test with 230V + 10% +10%? or just 230 +10% I wonder?

Test will certainly be done at 230 - 10%, at which voltage fuses may
remain intact while magic smoke is emitted by parts that the fuse is
meant to protect.
>
[snip]
>
>And of course there is the 50Hz issue which is not trivial for linear power 
>supplies.

What 50 Hz issue? Just that it's not 60 Hz, or something more subtle?
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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RE: rj45 with integrated magnetics..

[Gary McInturff]

The magnetics are made up of both a 1 to 1 isolation xformer and a cm choke. I
just stared at a schematic and I don't know if its an error, a single part or
generic, but for this one part the common mode choke was on the cable side for
the TX lines and on the IC side for the RX lines. I have never noticed that
before. I'll be looking at some other parts now that you have my interest
piqued.
Gary

From: Muhammad Sagarwala [mailto:msa...@force10networks.com]
Sent: Monday, February 03, 2003 9:00 AM
To: emc-p...@majordomo.ieee.org
Subject: rj45 with integrated magnetics..



Here is a question for you Gurus.. 

I was looked at a few different rj45 with integrated magnetics.  While all of
them were different in some respect, I found two major categories - one with
common mode choke on the chip (IC) side while others with common mode choke on
the cable side.  My question would be "why would one want to use a connector
with common mode choke on the chip side vs connector with common mode choke on
the cable side??? I wanted to know specific scenario where  a person would
prefer one over the other."  

Here I would like to add that most of the problems I have seen in my short
career are due to common mode noise making its way to the cable.  

Also, I would appreciate if someone could point me to a document where I could
find rules/factors to consider while selecting a jack with integrated
magnetics .

Muhammad 

Marking of packaging material

[Dave Wilson]

Can anyone point me to the tables in the annex of Decision 97/129, the ID
system for packaging covered by 94/62/EC? I can find the text, but not the
tables which presumably detail the numbering system.

Thanks,

Dave Wilson




  _  

Do you Yahoo!?
Yahoo! Mail Plus 
 - Powerful. Affordable. Sign up now http://mailplus.yahoo.com> 

Re: red tape and European voltage harmonization

[Ted Rook]

Does the old UK red-black-green colour code still exist anywhere I wonder?
India, Australia and South Africa the old Empire maybe?

There have been several requests here recently for guidance on the European
230V standardisation.

For non-Brits it may amuse you to know I can recall the Electricity Board
visiting everyone's houses in the mid 1950s in England to rerate appliances
for 240V from the old 220-230V. At that time they actually did up the nominal
voltage.

I concur with the statement made here that the supply companies in UK have not
changed a thing in response to the European harmonization. What has happened
is the tolerances have been changed and some of European zones at the low
limit are changing to a higher voltage very slowly.

Importers of voltage sensitive equipment into Europe should beware.

In the UK your equipment will be connected to 240V and will be expected to
work to specification. 
The upper limit should be 230 + 10% = 253V but don't hold your breath. Do UK
labs will test with 230V + 10% +10%? or just 230 +10% I wonder?

In rural Portugal and Greece you may find less than 220V for a long time to
come.

And of course there is the 50Hz issue which is not trivial for linear power
supplies.

The harmonization rules allow the UK electricity suppliers to gradually
changeover from 240V to 230V. The process has to be done on a regional basis
as obsolete equipment is replaced. And they have the choice to never change of
course.



Best Regards

Ted Rook, Console Engineering, ext 4659

Please note our new location and phone numbers:

Crest Audio Inc, 16-00 Pollitt Drive
Fair Lawn, NJ 07410 USA

201 475 4600 telephone receptionist, 8.30 - 5 pm EST.
201 475 4659 direct line w/voice mail, 24 hrs.
201 475 4677 fax, 24 hrs.




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Re: red tape

[Ravinder Ajmani]

Red Tape is a very common term used for describing the bureaucracy of
Government of India (perhaps a legacy from British).  Delays and inaction
by Indian bureaucracy have often been blamed to the Red Tape in the
government offices (which signifies a cloth ribbon tied around a file
folder to hold the papers in place).  One result of the criticism was that
the red tape was subsequently replaced with a white tape.  Although it is
anybody's guess, if this actually improved the working at the government
offices.

Regards, Ravinder
PCB Development and Design Department

Email: ajm...@us.ibm.com
***
Always do right.  This will gratify some people and astonish the rest.
 Mark Twain


  

  John Woodgate   

  To:  
emc-p...@majordomo.ieee.org  
  Sent by:  cc:   

  owner-emc-pstc@majordoSubject:  Re: red tape

  mo.ieee.org 

  

  

  02/03/2003 09:38 AM 

  Please respond to John  

  Woodgate

  

  






I read in !emc-pstc that Ted Rook  wrote (in
) about 'red tape' on Mon, 3 Feb 2003:

>red tape is an obstruction to progress while formal procedures are
completed.

OTOH, it's what I put over exposed mains connections while working on a
piece of equipment while it is powered.
--
Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to

http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Re: rj45 with integrated magnetics..

[neve...@attbi.com]

Hello Muhammad,

Sorry for the little lengthy reply, but it is one of the most important 
considerations when designing Ethernet front end - I tried to summarize it.

First you need to consider what kind of PHY driver you use. Some PHYs 
transmitters are supplied from the center taps (CT), some are not. This varies 
with the manufacturer. With the PHYs that use CT as a source of power for the 
Tx, you generally can't have a common-mode choke (CMC) on the PHY side,
because 
for the supply current to the TX that CM choke isn't CM, leading to supply 
voltage sags and preventing them to function properly. The PHYs that don't
take 
Tx power supply from the CT can have a CMC on the PHY side. Be sure to 
distinguish between PHYs that just bias the pairs from the CT (in which case 
you CAN use a CMC on the PHY side) vs. the ones that actually feed Tx power 
through the CT.

After this functional consideration, assume you have a case when you can use a 
CMC on the PHY side. CM voltage coupled to the pairs generates CM currents on 
the cables that cause most of the emission. On the PHY side of the
transformer, 
you can have CM voltage between the differential (I/O) pairs and the 
local "ground" plane. One typical source of CM on the pair, generated in the 
PHY, would be ground bounce over the package lead inductance. A CMC on the PHY 
side is excellent to provide low-pass filter. It is similar to RC filter, 
because the CMCs are mostly resistive (high-loss ferrite material) elements. 
Working in conjunction with the CT capacitor, it essentially reduces and
shunts 
the CM current and takes it back to the PHY (thus letting less CM current on 
the other side of the transformer). It works better than just a CT cap to 
filter the CM noise on the pair relative to the local reference "ground".

Ideally, this method with the CMC on the PHY side would leave near O V of CM 
voltage on the CT. Practically, this is very effective method to reduce CM 
voltage produced by, or coupled from the PHY, but leaves a possibility that
any 
noise on the "ground" planes escapes unimpeded to the UTP. Because of the 
imbalance in the CT of the transformers, lead inductance in the transformer 
package, and inductance through the CT capacitor, the effectiveness of this 
filter starts decreasing after about 200 (maybe 300) MHz.

Now about the potential problem when the CMC is on the PHY side. Depending on 
the design of your board and the system, you may have significant RF voltage 
between the chassis (front-panel) and the "ground" at the location of the 
center tap. When the only CMC is on the PHY-side, there is basically nothing
to 
prevent the voltage coupled from the "ground" to the CT from causing CM 
currents on the cable and emission. Therefore, it is very important to keep
the 
voltage of the "ground" plane to which the CT connects (usually through a cap) 
at very low levels relative to the I/O panel and chassis. The "ground" noise 
that may pop-up in emission scan is typically in the couple of hundreds MHz
and 
higher, because the "ground" inductance (impedance), can usually be kept 
relatively low (in well designed systems).

A CMC on the wire-side limits all CM currents, regardless of which segment of 
the transformer it is coupled into. However, you loose the benefit of RC-
filtering the low-frequency Ethernet noise that comes from the PHY.


Practical advice:
IF you are looking for best performance, IF you can afford it, and IF the 
functional requirement allows it, buy transformers with a low-frequency CMC on 
the PHY side AND with a high-frequency CMC on the cable side. Most practical 
designs are however limited to only one CMC per pair, and in that case I would 
always start design with a cable-side CMC. That is less expensive (less
ferrite 
cores in the part), works with any PHY, and the practice shows it suffices for 
EMC-compliant design.

Beware of CM-termination and autotransformers, since they can also provide a 
path for unwanted coupling across the CMC. I am refraining from discussing the 
CM termination here, it would take too much e-paper.

All previously said also applies to immunity considerations, just reverse the 
current path.

If you can get access to it, see Broadcom application note "10/100 and Gbit 
PHYs, EMC Design Guidelines". You'd need a password from your Broadcom rep to 
get it.

Neven

> Here is a question for you Gurus..
> 
> I was looked at a few different rj45 with integrated magnetics.  While all
of 
> them were different in some respect, I found two major categories - one with 
> common mode choke on the chip (IC) side while others with common mode choke
on 
> the cable side.  My question would be "why would one want to use a connector 
> with common mode choke on the chip side vs connector with common mode choke
on 
> the cable side??? I wanted to know specific scenario where  a person would 
> prefer one over the other."  
> 
> Here I would like to add that most of the problems I have seen in 

RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Peter L. Tarver]

I've had extensive discussion with UL regarding the
performance of this test.  Below are my comments, taken from
these discussions.

> -Original Message-
> From: Carl Newton
> Sent: Monday, February 03, 2003 9:20 AM
>
>
> 1.  Three samples are tested;

Intended to demonstrate repeatability of the test results.

> 2.  Trace resistance is measured before and after
> test.  Resistance cannot
>   exceed 0.1 ohms, and cannot change more
> than 10% after test;

The test datasheets I have from UL state the impedance
before and after applying the fault is measured using an
ohmmeter.  I intend to use a lower current version of the
earthing impedance test for this purpose (say, 20A, rather
than 40A).

> 3.  AC source is 240 Vac, 200 amps (20A circuit
> breaker X 10), power factor
>   is 75 - 80% through shorted bus bars with a
> 20/30 A (20 in my case)
> service
>   entrance type circuit breaker in series
> with the testing terminals.  The
> circuit
>   breaker is connected to the bus bars by
> 1.22 m (4 ft.) of #12 AWG wire.

Some of this information is for the UL lab technician, in
order to increase the reproducibility of the results and
protect their equipment.  For instance:

*no power factor is specified in CSA 22.2 No. 0.4
*bus bars are what exist in UL's lab and are not a
requirement to perform this test
*UL's power panels this test is derived from will likely be
capable of very large fault currents, so they will add
resistance to limit the current
*a service entrance circuit breaker is not necessary; this
was chosen for it's larger interrupting rating, so as to not
degrade the breaker too quickly under repeated fault
conditions; you can use a plain old branch circuit breaker.


> 4.  The test circuit is connected to the DUT via
> the grounding lead of the
>   1.82 m (6 ft) power supply cord.  If cord
> is not provided, then #16 AWG
>   wire is used.

It's anyone's guess why a No. 16

> 5.  Test continues until ultimate results occur;
> e.g. CB trips, trace opens,
> etc.
>
> Carl

The preliminary testing I've performed in my lab indicates
that the fault portion of the test can be over very quickly
(probably ms, but I haven't tried to measure it), even with
No. 18 AWG conductors and four connectorized interfaces
involved.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com



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RE: FCC Importation Issue

[craig.har...@jci.com]

The form that is mentioned below is FCC Form 740. If you go to
http://www.fcc.gov/ and type "FCC Form 740" in the search box. the first
item that comes up its the form. the second Item is a public notice
pertaining to the form

  We just ran into this issue with one of our products that was held in
customs. In the past it has not seemed to be an issue.

Thanks,

Craig


  
  
  jwise...@printronix.co  
  
  m  To: 
dclay...@nccn.net, emc-p...@majordomo.ieee.org 
  Sent by:   cc:  
  
  owner-emc-pstc@majordo Subject: RE: FCC
Importation Issue  
  mo.ieee.org 
  
  
  
  
  
  02/03/03 11:35 AM   
  
  Please respond to   
  
  JWiseman
  
  
  
  
  





Don,

Every now and then I get something stuck in US customs.  Typically the
agent will supply a form for FCC or CDRH compliance depending what is hung
and the reason.  If you fill out the paperwork the shipment proceeds.  If I
find a copy of the form here I will scan it in and send it to you directly.

The only time the above did not work for me was a power supply sample
coming in from Singapore.

Good Luck,
Josh


Has anyone out there had any problems with U.S. Customs
holding a product for lack of FCC report or a declartion
>from a manufacturer that product is indeed compliant?

Thanks in advance,

Don Clayton
ESR Engineering Inc.


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Re: red tape

[John Woodgate]

I read in !emc-pstc that Ted Rook  wrote (in
) about 'red tape' on Mon, 3 Feb 2003:

>red tape is an obstruction to progress while formal procedures are completed.

OTOH, it's what I put over exposed mains connections while working on a
piece of equipment while it is powered. 
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.

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 majord...@ieee.org
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Archive is being moved, we will announce when it is back on-line.
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Re: rj45 with integrated magnetics..

[j...@aol.com]

In a message dated 2/3/2003, Muhammad writes:




Also, I would appreciate if someone could point me to a document where I could
find rules/factors to consider while selecting a jack with integrated
magnetics.






Hi Muhammad:

One thing to watch out for with integrated magnetics is that some of these
designs do not do well with safety isolation and/or the lightning and power
cross requirements in Telcordia GR-1089 and EN 300 386-2.  For some
applications these standards are important, while for others they are not. 
Just make sure you know what your regulatory requirements are before you
commit to an RJ-45 with integrated magnetics.


Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848
j...@randolph-telecom.com
http://www.randolph-telecom.com

Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[cnew...@xycom.com]

Lou,

It's my impression that the typical switching power supply, such as
that  used for ITE type equipment, will apply basic insulation between
the primary circuits and earthed conductive parts on the primary side.
They do this in order to minimize the creepage/clearance requirements
and subsequently reduce the size of the supply.  I'm referring specifically
to Tables 2G and 2F of 60950.

Thanks,
 Carl




From: "Lou Aiken"  on 02/03/2003 01:46 PM

To:   Carl Newton/XYCOM@XYCOM, emc-p...@majordomo.ieee.org
cc:

Subject:  Re: EN60950 protective conductor test (was Re: Circuit Breaker
  Tripping Dring Fault Tests)



Carl, If the primary supply circuitry and components provide double or
reinforced insulation, nothing can become live in the event of a single
fault, the test becomes unnecessary, and I would argue that fact.

If the design does not provide double or reinforced insulation, the test
sounds applicable from points that could become live in case of a basic
insulation fault.

Regards,
Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
36561 USA

tel ++ 1 251 981 6786
fax ++ 1 251 981 3054
Cell ++ 1 251 979 4648

From: 
To: 
Sent: Monday, February 03, 2003 11:19 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)


>
>
>
> A slight divergence from the EN specifically, but I thought that the
> following would be helpful to this thread:
>
> I am presently working this issue with a UL engineer in accordance with
> UL 60950, 3rd Edition.   I also have the UL 60950 3rd Ed. Test Data
Sheets.
> Their "Protective Earthing Trace Earth Fault Current Test", UL Doc.
190.eng,
> per Section 2.6.3.3 requires the following in my case:
>
> 1.  Three samples are tested;
>
> 2.  Trace resistance is measured before and after test.  Resistance cannot
>   exceed 0.1 ohms, and cannot change more than 10% after test;
>
> 3.  AC source is 240 Vac, 200 amps (20A circuit breaker X 10), power
factor
>   is 75 - 80% through shorted bus bars with a 20/30 A (20 in my case)
> service
>   entrance type circuit breaker in series with the testing terminals.
The
> circuit
>   breaker is connected to the bus bars by 1.22 m (4 ft.) of #12 AWG
wire.
>
> 4.  The test circuit is connected to the DUT via the grounding lead of the
>   1.82 m (6 ft) power supply cord.  If cord is not provided, then #16
AWG
>   wire is used.
>
> 5.  Test continues until ultimate results occur; e.g. CB trips, trace
opens,
> etc.
>
> My UL guy tells me that I should expect the typical service type CB to be
rated
> up to  + 10%.  So it appears that  I need to concern myself with a burst
of
> current
> up to approximately 22 amps for the 20 amp AC circuit that my product is
being
> evaluated for.
>
> Carl
>
>
>
>
>
> From: "Chris Maxwell"  on 02/03/2003 09:29 AM
>
> Please respond to "Chris Maxwell" 
>
> To:   emc-p...@majordomo.ieee.org
> cc:(bcc: Carl Newton/XYCOM)
>
> Subject:  RE: EN60950 protective conductor test (was Re: Circuit Breaker
>   Tripping Dring Fault Tests)
>
>
>
>
> This thread has been interesting.  I am, at this moment, considering a
design
> where I am almost forced to use a PC (printed circuit) trace for Earth
ground.
>
> It seems funny to me that most equipment has been historically made with
18AWG
> protective ground pigtail wires; and 25A ground fault tests have been used
for
> years.
>
> Now that PC  traces are being used for protective ground; we want to test
with
> 200A or greater impulse currents?  I'm curious about what would happen to
your
> typical 18AWG line cord during this test.  I'm wondering if the line cord
would
> fuse open?
>
> There are a couple of handy charts on the web.
>
> One is at www.kepcopower.com/nomovax2.htm this is a nomograph of maximum
> operating current, AWG and IR drop in the conductor.  The point "A" is
generally
> considered the point of maximum IR drop.  If you draw a line from point
"A",
> through a wire gauge size; you'll get a max current.  Of course this is
steady
> state current; and the nomograph assumes a single wire.  Wire bundles
would be a
> worse case.  It's too bad that this chart doesn't contain the "fuse"
values for
> the wires as well (the  I squared * T values).
>
> Another is at www.circuitboards.com/capacity.php3.   This is a chart of
max
> current for PC traces.  Remember that this is for TRACES and planes only;
it
> doesn't say anything about vias and other potential problems.
>
> At first pass, it seems that a trace size to handle twice the power cord's
max
> current, (from the nomograph) with a 10degC trace temperature rise (from
the PC
> trace chart), would be a good rule of thumb for the trace size.  If I have
room,
> I'll just make it bigger.  Once we pay for the PC board fabrication, the
copper
> is free!
>
> Even with an  adequately sized trace; I can think of a few potential
problems
> with the trace to chassis connection:
>
> 1.  Many layout people open up PC traces or planes a

Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Lou Aiken]

Carl, If the primary supply circuitry and components provide double or
reinforced insulation, nothing can become live in the event of a single
fault, the test becomes unnecessary, and I would argue that fact.

If the design does not provide double or reinforced insulation, the test
sounds applicable from points that could become live in case of a basic
insulation fault.

Regards,
Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
36561 USA

tel ++ 1 251 981 6786
fax ++ 1 251 981 3054
Cell ++ 1 251 979 4648

From: 
To: 
Sent: Monday, February 03, 2003 11:19 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)


>
>
>
> A slight divergence from the EN specifically, but I thought that the
> following would be helpful to this thread:
>
> I am presently working this issue with a UL engineer in accordance with
> UL 60950, 3rd Edition.   I also have the UL 60950 3rd Ed. Test Data
Sheets.
> Their "Protective Earthing Trace Earth Fault Current Test", UL Doc.
190.eng,
> per Section 2.6.3.3 requires the following in my case:
>
> 1.  Three samples are tested;
>
> 2.  Trace resistance is measured before and after test.  Resistance cannot
>   exceed 0.1 ohms, and cannot change more than 10% after test;
>
> 3.  AC source is 240 Vac, 200 amps (20A circuit breaker X 10), power
factor
>   is 75 - 80% through shorted bus bars with a 20/30 A (20 in my case)
> service
>   entrance type circuit breaker in series with the testing terminals.
The
> circuit
>   breaker is connected to the bus bars by 1.22 m (4 ft.) of #12 AWG
wire.
>
> 4.  The test circuit is connected to the DUT via the grounding lead of the
>   1.82 m (6 ft) power supply cord.  If cord is not provided, then #16
AWG
>   wire is used.
>
> 5.  Test continues until ultimate results occur; e.g. CB trips, trace
opens,
> etc.
>
> My UL guy tells me that I should expect the typical service type CB to be
rated
> up to  + 10%.  So it appears that  I need to concern myself with a burst
of
> current
> up to approximately 22 amps for the 20 amp AC circuit that my product is
being
> evaluated for.
>
> Carl
>
>
>
>
>
> From: "Chris Maxwell"  on 02/03/2003 09:29 AM
>
> Please respond to "Chris Maxwell" 
>
> To:   emc-p...@majordomo.ieee.org
> cc:(bcc: Carl Newton/XYCOM)
>
> Subject:  RE: EN60950 protective conductor test (was Re: Circuit Breaker
>   Tripping Dring Fault Tests)
>
>
>
>
> This thread has been interesting.  I am, at this moment, considering a
design
> where I am almost forced to use a PC (printed circuit) trace for Earth
ground.
>
> It seems funny to me that most equipment has been historically made with
18AWG
> protective ground pigtail wires; and 25A ground fault tests have been used
for
> years.
>
> Now that PC  traces are being used for protective ground; we want to test
with
> 200A or greater impulse currents?  I'm curious about what would happen to
your
> typical 18AWG line cord during this test.  I'm wondering if the line cord
would
> fuse open?
>
> There are a couple of handy charts on the web.
>
> One is at www.kepcopower.com/nomovax2.htm this is a nomograph of maximum
> operating current, AWG and IR drop in the conductor.  The point "A" is
generally
> considered the point of maximum IR drop.  If you draw a line from point
"A",
> through a wire gauge size; you'll get a max current.  Of course this is
steady
> state current; and the nomograph assumes a single wire.  Wire bundles
would be a
> worse case.  It's too bad that this chart doesn't contain the "fuse"
values for
> the wires as well (the  I squared * T values).
>
> Another is at www.circuitboards.com/capacity.php3.   This is a chart of
max
> current for PC traces.  Remember that this is for TRACES and planes only;
it
> doesn't say anything about vias and other potential problems.
>
> At first pass, it seems that a trace size to handle twice the power cord's
max
> current, (from the nomograph) with a 10degC trace temperature rise (from
the PC
> trace chart), would be a good rule of thumb for the trace size.  If I have
room,
> I'll just make it bigger.  Once we pay for the PC board fabrication, the
copper
> is free!
>
> Even with an  adequately sized trace; I can think of a few potential
problems
> with the trace to chassis connection:
>
> 1.  Many layout people open up PC traces or planes around vias so that
only four
> little 20 mil wide bridges carry the current to the via.  This is great
for
> soldering heat relief; but BAD for current carrying capacity.  These
little
> bridges can fuse open in high current conditions.  I am considering
solving this
> by not putting any thermal reliefs around your Earth ground vias and using
> multiple vias.
>
> 2.  Another problem with these traces is using plated through vias with
screws
> through them.It has been found that plated through vias can crack when
they
> are put under pressure from screws.Some power supply manufacturers
solve
> this by bringing the Earth

MIl Spec - Vibration & Media Question

[me...@aol.com]

We have a customer that is writing a specification to purchase gauges that is
out of our rhelm of expertise.
   
 They need to know what MIL spec pertains to vibration and media pulsation
testing of pressure gauges.
   
They have also asked to know the scope of that particular spec. (or standard).

Anyone with some experience or direction for this?

Thanks

Chris



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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[cnew...@xycom.com]

A slight divergence from the EN specifically, but I thought that the
following would be helpful to this thread:

I am presently working this issue with a UL engineer in accordance with
UL 60950, 3rd Edition.   I also have the UL 60950 3rd Ed. Test Data Sheets.
Their "Protective Earthing Trace Earth Fault Current Test", UL Doc. 190.eng,
per Section 2.6.3.3 requires the following in my case:

1.  Three samples are tested;

2.  Trace resistance is measured before and after test.  Resistance cannot
  exceed 0.1 ohms, and cannot change more than 10% after test;

3.  AC source is 240 Vac, 200 amps (20A circuit breaker X 10), power factor
  is 75 - 80% through shorted bus bars with a 20/30 A (20 in my case)
service
  entrance type circuit breaker in series with the testing terminals.  The
circuit
  breaker is connected to the bus bars by 1.22 m (4 ft.) of #12 AWG wire.

4.  The test circuit is connected to the DUT via the grounding lead of the
  1.82 m (6 ft) power supply cord.  If cord is not provided, then #16 AWG
  wire is used.

5.  Test continues until ultimate results occur; e.g. CB trips, trace opens,
etc.

My UL guy tells me that I should expect the typical service type CB to be rated
up to  + 10%.  So it appears that  I need to concern myself with a burst of
current
up to approximately 22 amps for the 20 amp AC circuit that my product is being
evaluated for.

Carl





From: "Chris Maxwell"  on 02/03/2003 09:29 AM

Please respond to "Chris Maxwell" 

To:   emc-p...@majordomo.ieee.org
cc:(bcc: Carl Newton/XYCOM)

Subject:  RE: EN60950 protective conductor test (was Re: Circuit Breaker
  Tripping Dring Fault Tests)




This thread has been interesting.  I am, at this moment, considering a design
where I am almost forced to use a PC (printed circuit) trace for Earth ground.

It seems funny to me that most equipment has been historically made with 18AWG
protective ground pigtail wires; and 25A ground fault tests have been used for
years.

Now that PC  traces are being used for protective ground; we want to test with
200A or greater impulse currents?  I'm curious about what would happen to your
typical 18AWG line cord during this test.  I'm wondering if the line cord would
fuse open?

There are a couple of handy charts on the web.

One is at www.kepcopower.com/nomovax2.htm this is a nomograph of maximum
operating current, AWG and IR drop in the conductor.  The point "A" is
generally
considered the point of maximum IR drop.  If you draw a line from point "A",
through a wire gauge size; you'll get a max current.  Of course this is steady
state current; and the nomograph assumes a single wire.  Wire bundles would be
a
worse case.  It's too bad that this chart doesn't contain the "fuse" values for
the wires as well (the  I squared * T values).

Another is at www.circuitboards.com/capacity.php3.   This is a chart of max
current for PC traces.  Remember that this is for TRACES and planes only; it
doesn't say anything about vias and other potential problems.

At first pass, it seems that a trace size to handle twice the power cord's max
current, (from the nomograph) with a 10degC trace temperature rise (from the PC
trace chart), would be a good rule of thumb for the trace size.  If I have
room,
I'll just make it bigger.  Once we pay for the PC board fabrication, the copper
is free!

Even with an  adequately sized trace; I can think of a few potential problems
with the trace to chassis connection:

1.  Many layout people open up PC traces or planes around vias so that only
four
little 20 mil wide bridges carry the current to the via.  This is great for
soldering heat relief; but BAD for current carrying capacity.  These little
bridges can fuse open in high current conditions.  I am considering solving
this
by not putting any thermal reliefs around your Earth ground vias and using
multiple vias.

2.  Another problem with these traces is using plated through vias with screws
through them.It has been found that plated through vias can crack when they
are put under pressure from screws.Some power supply manufacturers solve
this by bringing the Earth ground trace to the surface with vias near the
chassis connection point; then route this to a solid plated pad on the surface
layer for chassis connection.  I am considering this same solution as well.

3.  The third problem is mechanical.  Once Earth ground brought to a pad on the
circuitboard; then there is still the issue of getting a good mechanical mate
to
the chassis with a wide surface area.  If the connection is made through a
couple of teeth on a star washer; then there is a potential for localized
heating.   I'm just going to maximize surface contact area for this one.  I'm
also considering using multiple board to chassis connection locations.  Every
screw that connects the board to chassis is a potential Earth ground
connection.

The last "fuse" in any power system is the cord connected to the product.  It
seems to me, (ju

rj45 with integrated magnetics..

[Muhammad Sagarwala]

Here is a question for you Gurus.. 

I was looked at a few different rj45 with integrated magnetics.  While all of
them were different in some respect, I found two major categories - one with
common mode choke on the chip (IC) side while others with common mode choke on
the cable side.  My question would be "why would one want to use a connector
with common mode choke on the chip side vs connector with common mode choke on
the cable side??? I wanted to know specific scenario where  a person would
prefer one over the other."  

Here I would like to add that most of the problems I have seen in my short
career are due to common mode noise making its way to the cable.  

Also, I would appreciate if someone could point me to a document where I could
find rules/factors to consider while selecting a jack with integrated
magnetics .

Muhammad 

FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS

[Sketoe, James G]

This is a multi-part message in MIME format.

Failed to attach the file.


jgs

Jim Sketoe
M/C S106-3050
(314)232-4782 (Voice)
(314)232-7391 (Fax)



From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com]
Sent: Thursday, January 23, 2003 9:15 AM
To: 'IEEE EMC-PSTC GROUP'
Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS



All
I would like to construct a Helmholtz coil to perform magnetic field
immunity testing at DC frequencies and thus simulate the effect of a
permanent magnet. There are some details on construction in EN61000-4-8
which details power frequency magnetic field immunity testing within the
scope of the EMC directive. However the fields referred to are measured in
A/m, whereas I need a field of, for example, 5mTesla.
Can anybody advise me as to how to construct such a coil with a test volume
of 0.5 x 0.5 x 0.5m and a field of 5mTesla?
Thanks
Ian Gordon
 

_
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Title: FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS







Failed to attach the file.


    

jgs


Jim Sketoe

M/C S106-3050

(314)232-4782 (Voice)

(314)232-7391 (Fax)



-Original Message-

From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com]

Sent: Thursday, January 23, 2003 9:15 AM

To: 'IEEE EMC-PSTC GROUP'

Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS




All

I would like to construct a Helmholtz coil to perform magnetic field

immunity testing at DC frequencies and thus simulate the effect of a

permanent magnet. There are some details on construction in EN61000-4-8

which details power frequency magnetic field immunity testing within the

scope of the EMC directive. However the fields referred to are measured in

A/m, whereas I need a field of, for example, 5mTesla.

Can anybody advise me as to how to construct such a coil with a test volume

of 0.5 x 0.5 x 0.5m and a field of 5mTesla?

Thanks

Ian Gordon

 


_

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RUBENS.DOC
Description: Binary data

FW: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS

[Sketoe, James G]

This sounds much like what I call Rubens Coil.  The attached Word doc
describes the unit.

Mr. Rubens deserves the credit.

jgs

Jim Sketoe
M/C S106-3050
(314)232-4782 (Voice)
(314)232-7391 (Fax)



From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com]
Sent: Thursday, January 23, 2003 9:15 AM
To: 'IEEE EMC-PSTC GROUP'
Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS



All
I would like to construct a Helmholtz coil to perform magnetic field
immunity testing at DC frequencies and thus simulate the effect of a
permanent magnet. There are some details on construction in EN61000-4-8
which details power frequency magnetic field immunity testing within the
scope of the EMC directive. However the fields referred to are measured in
A/m, whereas I need a field of, for example, 5mTesla.
Can anybody advise me as to how to construct such a coil with a test volume
of 0.5 x 0.5 x 0.5m and a field of 5mTesla?
Thanks
Ian Gordon
 

_
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Scanning Service - powered by MessageLabs. For further information visit
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RE: FCC Importation Issue

[Joshua Wiseman]

Don,

Every now and then I get something stuck in US customs.  Typically the agent
will supply a form for FCC or CDRH compliance depending what is hung and the
reason.  If you fill out the paperwork the shipment proceeds.  If I find a
copy of the form here I will scan it in and send it to you directly.

The only time the above did not work for me was a power supply sample coming
in from Singapore.

Good Luck,
Josh


Has anyone out there had any problems with U.S. Customs
holding a product for lack of FCC report or a declartion
>from a manufacturer that product is indeed compliant?

Thanks in advance,

Don Clayton
ESR Engineering Inc.


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red tape

[Ted Rook]

English colloquialism

'red tape'  is found in large quantities in organizations which have the power
to approve or impede the work of others.

originally: the legal papers used in courts of justice are closed with a piece
of red material

so by implication

red tape is an obstruction to progress while formal procedures are completed.

Best Regards

Ted Rook, Console Engineering, ext 4659

Please note our new location and phone numbers:

Crest Audio Inc, 16-00 Pollitt Drive
Fair Lawn, NJ 07410 USA

201 475 4600 telephone receptionist, 8.30 - 5 pm EST.
201 475 4659 direct line w/voice mail, 24 hrs.
201 475 4677 fax, 24 hrs.




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Lead Free

[Enci]

Has anyone actually tried it? What are your experiences?

What do non-EU countries think about it?



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RE: single fault conditions

[Price, Ed]

>-Original Message-
>From: Rich Nute [mailto:ri...@sdd.hp.com]
>Sent: Friday, January 31, 2003 4:17 PM
>To: j...@jmwa.demon.co.uk
>Cc: emc-p...@majordomo.ieee.org
>Subject: Re: single fault conditions
>
>
>
>
>
>
>Hi John:
>
>
>>   >For example, at a previous employer, I observed several 
>instances of FETs
>>   >(in a 3kVA instrument) exploding and sending molten metal 
>(mostly from the
>>   >leads and the lead's solder pads) through chassis vents, 
>that subsequently
>>   >caused the surrounding cheesecloth to ignite. 
>>   
>>   WOW! I wouldn't have though that there would be enough 
>energy in the
>>   droplets after their flight through the air to cause 
>ignition. Did you
>>   treat the cheesecloth with potassium nitrate solution 
>before the test?
>
>Molten metal has:
>
>high temperature
>high stored energy
>high thermal conductivity
>
>A small drop (1-2 mm diameter) of molten 
>copper falling through about 0.4 meter 
>will ignite non-flame-retardant plastic 
>material (I've done the test and have the 
>pix).
>
>Very much smaller pieces would ignite
>unalduterated cheesecloth.
>
>
>Best regards,
>Rich



Rich:

I first performed this test in 1965, albeit with certain modifications.

I applied a molten glob of 60/40 alloy solder, through a 0.5 meter fall from
a soldering iron, into the interstitial space between my leather shoe and
Orlon sock. I did not experience synthetic fabric ignition, but I certainly
did achieve lift-off (as I hopped around the lab trying to rip off my boot).

In addition to pioneering this test method, I also think I invented disco
that day.


Ed

Ed Price
ed.pr...@cubic.com
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA  USA
858-505-2780  (Voice)
858-505-1583  (Fax)
Military & Avionics EMC Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis


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RE: Proposed new EMC Directive.

[richwo...@tycoint.com]

I also recommend reading this guide.
 
http://europa.eu.int/comm/enterprise/ne
approach/legislation/guide/legislation.htm
 
See section 3 concerning private branded products.
 
Richard Woods 
Sensormatic Electronics 
Tyco International 


From: WOODS, RICHARD 
Sent: Friday, January 31, 2003 1:43 PM
To: IEEE Forum (E-mail)
Subject: RE: Proposed new EMC Directive. 


Ian, I recommend that you visit the European Commission's EMC web site:
http://europa.eu.int/comm/enterprise/electr_equipment/emc/index.htm
 
You will find a guide that describes the file requirements and your
obligations for reselling a private branded product. The basic requirements
are not going to change with the revised directive.
 
Richard Woods 
Sensormatic Electronics 
Tyco International 


From: White, Ian [mailto:ianwh...@spiraxsarco.com]
Sent: Friday, January 31, 2003 11:34 AM
To: IEEE Forum (E-mail)
Subject: Proposed new EMC Directive. 


Hi everyone.
 
We have been working through consequences of the New Proposed Emc Directive.
As we are not a large electronics company so we will not be able to quote all
the standards  we quoted today as we don't use equipment detailed in that said
standard. 
 
The new directive states we will have to establish technical documentation
which enables conformity to be assed, which would include design and
manufacturing information as well as test results. No doubt detailing the
instrumentation used as well.
 
This is going to make for a very large file for each product. 
 
There is also the point, that we buy in products and put the Spirax label on
it. 
 
Upto this point we have excepted a suppliers D of C. Across the company this a
large number of products. 
 
We would be left assessing if a supplier was complying by reading his
technicial documentation. The amount of paperwork this would entail is a bit
overpowering to think about.
 
Have we been reading the Proposed EMC Directive correctly ?
 
Thanks
 
Ian
 
 
 

RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Chris Maxwell]

This thread has been interesting.  I am, at this moment, considering a design
where I am almost forced to use a PC (printed circuit) trace for Earth ground.

It seems funny to me that most equipment has been historically made with 18AWG
protective ground pigtail wires; and 25A ground fault tests have been used for
years.  

Now that PC  traces are being used for protective ground; we want to test with
200A or greater impulse currents?  I'm curious about what would happen to your
typical 18AWG line cord during this test.  I'm wondering if the line cord
would fuse open? 

There are a couple of handy charts on the web.

One is at www.kepcopower.com/nomovax2.htm this is a nomograph of maximum
operating current, AWG and IR drop in the conductor.  The point "A" is
generally considered the point of maximum IR drop.  If you draw a line from
point "A", through a wire gauge size; you'll get a max current.  Of course
this is steady state current; and the nomograph assumes a single wire.  Wire
bundles would be a worse case.  It's too bad that this chart doesn't contain
the "fuse" values for the wires as well (the  I squared * T values).

Another is at www.circuitboards.com/capacity.php3.   This is a chart of max
current for PC traces.  Remember that this is for TRACES and planes only; it
doesn't say anything about vias and other potential problems.  

At first pass, it seems that a trace size to handle twice the power cord's max
current, (from the nomograph) with a 10degC trace temperature rise (from the
PC trace chart), would be a good rule of thumb for the trace size.  If I have
room, I'll just make it bigger.  Once we pay for the PC board fabrication, the
copper is free!

Even with an  adequately sized trace; I can think of a few potential problems
with the trace to chassis connection:

1.  Many layout people open up PC traces or planes around vias so that only
four little 20 mil wide bridges carry the current to the via.  This is great
for soldering heat relief; but BAD for current carrying capacity.  These
little bridges can fuse open in high current conditions.  I am considering
solving this by not putting any thermal reliefs around your Earth ground vias
and using multiple vias.

2.  Another problem with these traces is using plated through vias with screws
through them.It has been found that plated through vias can crack when
they are put under pressure from screws.Some power supply manufacturers
solve this by bringing the Earth ground trace to the surface with vias near
the chassis connection point; then route this to a solid plated pad on the
surface layer for chassis connection.  I am considering this same solution as
well.

3.  The third problem is mechanical.  Once Earth ground brought to a pad on
the circuitboard; then there is still the issue of getting a good mechanical
mate to the chassis with a wide surface area.  If the connection is made
through a couple of teeth on a star washer; then there is a potential for
localized heating.   I'm just going to maximize surface contact area for this
one.  I'm also considering using multiple board to chassis connection
locations.  Every screw that connects the board to chassis is a potential
Earth ground connection.

The last "fuse" in any power system is the cord connected to the product.  It
seems to me, (just an opinion now) that a Earth ground system made to handle
the worst case current of your worst case power input cable (along with some
design margin) would stand a good chance of passing any regulatory test.  

Can any of the gurus see a problem with this?

Chris Maxwell | Design Engineer - Optical Division
email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024

NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA
web www.nettest.com | tel +1 315 797 4449 | 







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Unity power factor

[Neil Helsby]

With reference to the Fluke Application Note suggested by Rich and 
commented on by John.

All I get on visiting the site is "404 Page not found error" on their 
home page. Access to all other pages seems to be ok. Using their search 
engine facility does not seem to find anything with respect to 
application notes or harmonics. Anyone else have this problem?

Regards,

Neil Helsby


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Re: EN60950 protective conductor test

[Lou Aiken]

I support both John's opinions.

I don't want PC traces for PE circuits outlawed in the standards because
there may be some valid reason to do that, but I have never come across it
in ITE or domestic appliances.

Based on my experience all mains circuits are provided with double or
reinforced insulation. I believe the cost hit for that construction can be
essentially nothing.

Consequently nothing is connected to the so-called PE trace (or more
correctly, a PC trace connected to the product's earthing means) except the
approved Y caps, and possibly one or more SELV circuits.

When inexperienced test engineers mentioned high current withstand of  PC
traces, I  point out that the mains circuits cannot fault to earthed
circuits as a result of a single fault.  Therefore, the test is not
required.

Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
36561 USA

tel ++ 1 251 981 6786
fax ++ 1 251 981 3054
Cell ++ 1 251 979 4648

From: John Woodgate 
To: 
Sent: Saturday, February 01, 2003 3:12 PM
Subject: Re: EN60950 protective conductor test


>
> I read in !emc-pstc that Rich Nute  wrote (in
> <200302012030.maa04...@epgc264.sdd.hp.com>) about 'EN60950 protective
> conductor test' on Sat, 1 Feb 2003:
> >>   short-circuit conditions. The printed-board mounting versions of the
IEC
> >>   60320 appliance connector encourage the use of board traces to carry
the
> >>   PEC; something that I would not be happy about, in principle.
> >
> >Such construction cannot be sloughed off in such
> >an off-hand manner.  This is solo BOGSAT
> >engineering, which cannot be condoned.
>
> Is it not permitted to express a personal preference on this group? I
> *prefer, personally*, not to use printed board traces as parts of the
> PEC. I'm not suggesting that should be in IEC 60950 or any other
> standard.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
> Interested in professional sound reinforcement and distribution? Then go
to
> http://www.isce.org.uk
> PLEASE do NOT copy news posts to me by E-MAIL!
>
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
>
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>



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