RE: ESD generators max Contact discharge level

[Gary McInturff]

Hi Chris,
I agree with your whole heartedly. If it weren't for people there
wouldn't be an ESD problem. We are wither walking around charging others
stuff like furniture or worse yet we charge ourselves and the go around
touching stuff. For the most part I know of nobody that is able to hold a
charge until they contact a surface and then dump it to ground at will. Even
though somewhat less repeatable I think the test should attempt to model the
discharge mode - Through air as people approach the equipment.
I also have a hunch, and I have no data nor have I studied real
hard, but I believe that if the guns are designed be more and more alike, a
great deal of the variability goes out of the test. The test operator comes
next, but they can be trained for reasonable repeatability when the are
taught some of the issues. 
Even some of that gets leveled out if the test is run carefully and
uses multiple test levels, say every 2k or even at 1K increments.
Gary

-Original Message-
From: Chris Maxwell [mailto:chris.maxw...@gnnettest.com]
Sent: Monday, April 23, 2001 11:36 AM
To: 'EMC-PSTC Internet Forum'
Subject: FW: ESD generators max Contact discharge level



> Hi Ed,
> 
> I fully agree that membrane keypads are one of the most common places
> where a finger could discharge to the instrument.
> 
> However, I disagree that contact discharge is the appropriate test method
> for these surfaces. Current state of the art in test instruments and
> methods dictates air discharge testing of such surfaces. Just for
> clarity's sake, when I say air discharge testing, I mean approaching the
> device under test with a blunt, charged ESD gun tip.  If the device under
> test has a weak insulator, an air discharge will occur. 
> 
> The IEC standards use contact discharge testing as the "preferred" method
> because it is more repeatable than air discharge testing.  The IEC
> standards recognize air discharge testing on surfaces that won't allow a
> contact discharge.   
> 
> I could write a book explaining why air discharge testing is the closest
> simulation to real life (unless you're in a vacuum) and another book about
> why contact discharge is used as  a repeatable model for air discharges
> but I'll spare everyone the details. I could explain more fully if anyone
> is interested.
> 
> The manual for my ESD gun (Keytek MiniZap, which is a compliance grade
> instrument) recommends against contact discharges to insulated surfaces as
> it has the potential to damage the high voltage relay in the product.  I
> can't speak for other guns. 
> .  
> For insulated membrane switches, the IEC standards and the equipment that
> I have dictates that I use air discharge testing.  
> 
> Until a better test method comes along, I stand by my original answer to
> Dan's question.
> 
> Best regards,
> 
> Chris
> 
> P.S.  Being forever curious,  If anyone knows of an ESD simulator or test
> method that does perform contact discharges to insulated surfaces, I'd
> love to hear about it.  I'm sure that it would be of interest to the group
> as well. 
> 
> 
>  Ed's email attached *
> 
> 
> Chris:
> 
> I don't understand why a membrane switchpad would not be tested for
> contact
> discharge. It think that this is the absolutely most likely place where a
> finger, attached to a charged human body, might be applied to the EUT. It
> seems to me that you would want to be testing the dielectric strength of
> the
> insulation over the keypad conductive traces.
> 
> The issue of whether a triggering of the testing gun, without a completed
> discharge current, would damage the gun, isn't relevant to the need for
> the
> test. Dumping 15 or 20 kV to a probe tip, while not exactly trivial, still
> shouldn't be critically sensitive to load conditions. 
> 
> Regards,
> 
> Ed
> 
>

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the

CPSTC safety chapter meeting for May 2, 2001

[RichardG]

Greetings,

For those of you who are interested in attending the Colorado Product Safety
Technical Committee (CPSTC) meeting, please read on.

If you plan on attending, please let me know by Friday April 27, 2001, so I
can plan accordingly with the food and drinks. Also, if you need a map, let
me know.

Please note:

For the meeting scheduled for May 2, 2001, it will be hosted by Mat
Aschenberg  (mailto:mat.aschenb...@echostar.com), located at -

EchoStar Technologies Corporation
94 Inverness Circle East
Englewood, CO 80112 

Start time: 6:30pm
End time: 8:30pm

Agenda 
1. Agenda for year 2001 
2. Review the progress of:
a. The presentation by Ron Duffy and Richard Georgerian for the IEEE
EMC Montreal Symposium PS Workshop .
b. Review the progress of Bill LaFollette regarding his transformer
technical paper.
3. Topics of discussion:
a. Demonstration of the capacitive discharge circuit that Exabyte is
developing for an internal and/or external piece of safety test equipment.
b. If possible, Ron Duffy to give a brief review of his Hazard-Based
Seminar that he teaches for Agilent's internal use.


Thanks in-advance.

Richard Georgerian
Technical Committee 8 Product Safety (TC-8), Vice-chair
Colorado Product Safety Technical Committee (CPSTC), Chair
Product Compliance Engineer
Exabyte
1685 38th Street
Boulder, CO 80301
USA
tel.: 303-417-7537  fax: 303-417-5710   email:
 

RE: ESD generators max Contact discharge level

[McCoy, Paul]

Ed,
Desirability may be a moot point. Whether you want to test the
membrane keypad as a contact discharge or not the test equipment may not let
you. The Haefly-Trench ESD gun (PESD 1600?) for one checks continuity
through the tip before it enables a contact discharge. If you pull the
trigger and there is no continuity it displays a message to that effect and
waits to be reset (trigger release). 
To the second point I agree with Chris that contact discharge is
only valid for conductive surfaces. The standard prefers contact discharge
WHERE APPLICABLE (emphasis mine) because it is a more repeatable test. It
doesn't have the variables of approach speed and such that air discharge
does. It does need a conductive surface to be valid. Your example of the
membrane being a must test point due to real world considerations is well
taken; but the real world event it sees is an air discharge (which is not a
defining criteria, the defining criteria is if you have a conductive surface
do a contact discharge, even if the real world threat is an air discharge)
and do to its physical characteristics (non-conductive) it is tested with an
air discharge. 
This is based on definitions and test procedures for IEC 1000-4-2
and EN 61000-4-2. there may be different requirements in other ESD test
standards. There is at least one commercially available ESD gun that will
only allow you test in the manner I describe.

Paul McCoy

-Original Message-
From: Price, Ed [mailto:ed.pr...@cubic.com]
Sent: Monday, April 23, 2001 9:47 AM
To: emc-p...@ieee.org
Subject: RE: ESD generators max Contact discharge level





>-Original Message-
>From: Chris Maxwell [mailto:chris.maxw...@gnnettest.com]
>Sent: Monday, April 23, 2001 4:45 AM
>To: 'Dan Kinney (A)'; Douglas C. Smith; Terry Meck
>Cc: emc-p...@ieee.org
>Subject: RE: ESD generators max Contact discharge level
>
>
>
>Hi Dan,
>
>Air discharges are made anywhere on the product where an 
>insulator covers
>possibly sensitive features.  
>
>Membrane keypads are a great example.  The keypads contain traces and
>circuitry that may be sensitive to ESD.  However, since the 
>outermost layer
>is an insulator, making a contact discharge would not be a 
>real world test.
>I believe that it may also damage the contact discharge relay 
>in certain ESD
>generators.   I can explain that in more detail if you would 
>like.  In my
>experience, membrane keypads are always tested with air discharge.
>

SNIP

>
>Chris Maxwell
>Design Engineer
>NetTest
>6 Rhoads Drive, Building 4
>Utica,NY 13502
>email: chris.maxw...@gnnettest.com
>phone:  315-266-5128
>fax: 315-797-8024
>

Chris:

I don't understand why a membrane switchpad would not be tested for contact
discharge. It think that this is the absolutely most likely place where a
finger, attached to a charged human body, might be applied to the EUT. It
seems to me that you would want to be testing the dielectric strength of the
insulation over the keypad conductive traces.

The issue of whether a triggering of the testing gun, without a completed
discharge current, would damage the gun, isn't relevant to the need for the
test. Dumping 15 or 20 kV to a probe tip, while not exactly trivial, still
shouldn't be critically sensitive to load conditions. 

Regards,

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 Services Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

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

RE: 2. 4 GHz cordless telephone, question of general interest

[Gary McInturff]

I once was in a hurry to get out the door to a racquetball game. My
shorts were still damp and I got to thinking about how microwave ovens work
and their effects of the  on water content of items. Rapidly following a
flawed string of logic I decided the microwave would a quick solution to my
problem. 
Not being a complete idiot (please I know many of you will have some
pretty interesting things to say on the point but spare me for the moment if
you will!) I put them in the oven and set it for a minute. Pulled them out,
and discovered it was working, tried two minutes. - still working so now I
am on to a plan. About this time a neighbor showed up and needed some tools
in my garage. Flush with my recent success I set the ol' microwave to 5
minutes and I'm off in the garage digging for tools and pointing out to my
neighbor what a clever fellow I was. 
I gave him the tools and returned to the kitchen, yanked open the
microwave and was greeted by small puffs of smoke rolling out of the oven
door. It seems I had failed to account for the nylon stitching around the
garment halves and waste band. Five minutes was enough to build enough heat
in those areas to scorch the cloth. Some of the hems were on the centerline
front to back but I was out of time; and widely thought I should be the hell
out of the kitchen before my wife discovered all of this, so off I went.
Once at the gym I put on the shorts and headed for the court. Well,
given the burn patterns a lot of folks just assumed I had the worse case of
"burrito gas discharge and vaporization" they had ever witnessed. The extra
attention didn't help my game any, and now I'm not allowed in the kitchen.
Gary

-Original Message-
From: Cortland Richmond [mailto:72146@compuserve.com]
Sent: Monday, April 23, 2001 7:36 AM
To: David Instone; ieee pstc list
Subject: Re: 2. 4 GHz cordless telephone, question of general interest



A lump of coal will heat up in a microwave oven. No water needed. It is the
bulk resistivity of an object which allows circulating currents to generate
heat, and while water can help (when we wet something, its chemical bonds
are a source of electrons) it is not the only thing that is heated in a
microwave oven.

The cones from our chambers don't have water in them (better not, anyway)
and they'll not only heat up in the microwave, but burn with a nasty, nasty
smell. The carbon conducts, the foam that holds it burns. Not to denigrate
water's action; I remember reading that a serviceable Radar Absorbing
Material may be made by wetting foam urethane. But the frequency of
microwave ovens wasn't chosen for resonance with water.

(PURE, distilled water is an insulator. I wonder if 2450 is close enough to
even warm it up?)

Cortland


== Original Message Follows 

 >> Date:  23-Apr-01 02:07:07  MsgID: 1078-34037  ToID: 72146,373
From:  David Instone >INTERNET:david_inst...@uk.xyratex.com
Subj:  Re: 2. 4 GHz cordless telephone, question of general interest
Chrg:  $0.00   Imp: Norm   Sens: StdReceipt: NoParts: 1

List-Post: emc-pstc@listserv.ieee.org
Date: Mon, 23 Apr 2001 09:05:38 +0100
From: david_inst...@uk.xyratex.com (David Instone)
Subject: Re: 2. 4 GHz cordless telephone, question of general interest
Reply-To: david_inst...@uk.xyratex.com (David Instone)
 

Ken Javor wrote:
> 
> Just goes to show you can find anything on the net.  I have measured
leakage
> from microwave ovens and every one was at 2450 MHz.  And that IS a
resonant
> frequency for water and water alone.  That's why you can put waterless
items
> in and they won't heat up,

Hm, now I wonder how the the totally dry and empty pottery plate I put
in the microwave to heat (before I put my non microwave cooked food on
it) gets too hot to hold after just 60 seconds at 650W.


> and also why you should never run a microwave
> oven without a water load: with no load you get high vswr and the
magnetron
> can be damaged by reflected energy.
-- 
Regards

Dave Instone. Compliance Engineer
 Storage Systems Development, MP24/22
 Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
Tel: +44 (0)23-92-496862 (direct line)
Fax: +44 (0)23-92-496014
http://www.xyratex.com  Tel: +44 (0)23-92-496000

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click o

FW: ESD generators max Contact discharge level

[Chris Maxwell]

> Hi Ed,
> 
> I fully agree that membrane keypads are one of the most common places
> where a finger could discharge to the instrument.
> 
> However, I disagree that contact discharge is the appropriate test method
> for these surfaces. Current state of the art in test instruments and
> methods dictates air discharge testing of such surfaces. Just for
> clarity's sake, when I say air discharge testing, I mean approaching the
> device under test with a blunt, charged ESD gun tip.  If the device under
> test has a weak insulator, an air discharge will occur. 
> 
> The IEC standards use contact discharge testing as the "preferred" method
> because it is more repeatable than air discharge testing.  The IEC
> standards recognize air discharge testing on surfaces that won't allow a
> contact discharge.   
> 
> I could write a book explaining why air discharge testing is the closest
> simulation to real life (unless you're in a vacuum) and another book about
> why contact discharge is used as  a repeatable model for air discharges
> but I'll spare everyone the details. I could explain more fully if anyone
> is interested.
> 
> The manual for my ESD gun (Keytek MiniZap, which is a compliance grade
> instrument) recommends against contact discharges to insulated surfaces as
> it has the potential to damage the high voltage relay in the product.  I
> can't speak for other guns. 
> .  
> For insulated membrane switches, the IEC standards and the equipment that
> I have dictates that I use air discharge testing.  
> 
> Until a better test method comes along, I stand by my original answer to
> Dan's question.
> 
> Best regards,
> 
> Chris
> 
> P.S.  Being forever curious,  If anyone knows of an ESD simulator or test
> method that does perform contact discharges to insulated surfaces, I'd
> love to hear about it.  I'm sure that it would be of interest to the group
> as well. 
> 
> 
>  Ed's email attached *
> 
> 
> Chris:
> 
> I don't understand why a membrane switchpad would not be tested for
> contact
> discharge. It think that this is the absolutely most likely place where a
> finger, attached to a charged human body, might be applied to the EUT. It
> seems to me that you would want to be testing the dielectric strength of
> the
> insulation over the keypad conductive traces.
> 
> The issue of whether a triggering of the testing gun, without a completed
> discharge current, would damage the gun, isn't relevant to the need for
> the
> test. Dumping 15 or 20 kV to a probe tip, while not exactly trivial, still
> shouldn't be critically sensitive to load conditions. 
> 
> Regards,
> 
> Ed
> 

>

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: Job Description

[Gorodetsky, Vitaly]

Doug -

Quoting our new President, you are "misunderestimate" yourself in item 15
particularly. 

Also, I believe it is relevant to quote one of  Scott Adams' refreshing
observations (11/5/00).  
" - Starting today, the Job requires a Ph.D.
-   Whew!  Luckily, I have a Ph.D.
-   You do?  Well, the Job also requires an Olympic Gold Medal."

Best Regards,
Vitaly  Gorodetsky

The suitability of this information for making decision is solely with the
reader


-Original Message-
From:   Doug McKean [mailto:dmck...@gte.net]
Sent:   Saturday, April 21, 2001 12:17 PM
To: emc-p...@ieee.org
Subject:RE: Job Description


Oh, something like 

This person SHALL 

1. Address any compliance/agency issues during the 
   entire life cycle of a product starting with 
   product development, maintanence of approvals 
   through product release, and finally with product 
   obsolescence. 

2. This will require someone to be proactive in 
   both design and manfacturing phases of a product. 

3. Perform any prelimenary testing where possible. 

4. Manage product compliance testing with the appropriate 
   test labs and agencies. 

5. Maintain all documents of product approval. 

6. Manage sustaining compliance issues during the life 
   cycle of a product after manufacturing release. 

7. Be involved in the ECR/ECO process where changes 
   could compromise agnecy approvals of products. 

8. Will expected to work either independently or 
   within groups. 

9. Must have a working knowledge of the following: 
   the pertinent standards to which the product is 
   being tested,  EMC to include printed circuit 
   board design techniques, safety issues to include 
   any possible liability issues with said product, 
   any possible National Electrical Codes within 
   said country, bills of materials, ECR/ECO processes 
   used by this or any other company with which this 
   companies does OEM arrangements. 

10. BS expected.  
MS preferrred.  
PE desired. (any state license is sufficient but 
 all of them is desired ...) 

11. Multi-lingual in at least 5 languages. 

12. Be able to correct hardware design in a blink. 

13. Have enough brass to call a "stop ship" at any time. 

13. And then once hired, expect to be generally ignored ... 

14. Must be willing to work lots of overtime without 
being asked. 

15. Pay approx  $35K max ...  

Regards, Doug McKean 


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

Visit our web site at:
http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web
at:
http://www.rcic.com/  click on "Virtual Conference
Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: Transformer Question

[Pham, Tac]

Ken,

Depend on the type of transformer, such as isolating or signal, you should
be aware of the following:

1. The temperature rating would dictate the insulation class A (105), B
(130), and so on... in accordance with IEC85. These insulating systems will
identify the tapes, wires, plastic material, varnish. Every time you request
for the substitution of these component, you must ensure that new components
are specified in the insulation system.

2. It does not matter that your company or your vendors manufactured this
transformer, UL will require a copy of winding sheet, a BOM for review, that
including type of tapes, bobbin material, sleeving... and constructional
such as margin, creepage.

3. Your transformer is customized and use in only one power supply model, it
is not required this xfmr bear the UL recognition mark. Many manufacturers
provides the UL recognition mark on transformers , but the end-users must
verify the thermal, short circuit test... per specific application.

4. If you have a second source (more than one vendor) for this xfmr, then
your report must identify all vendors and theirs insulation system.

Please note that only UL has this requirement, other agencies determine the
temperature class by the rating of material without additional tests as an
insulation system. 

Tac Pham
Power-One TSD
949-261-2200




-Original Message-
From: Matsuda, Ken [mailto:matsu...@curtisinst.com]
Sent: Saturday, April 21, 2001 1:38 AM
To: emc-p...@ieee.org
Subject: Transformer Question



Group,

I was wondering if you could help me with this one?  Currently, I have a
switching power supply, using custom transformers. Now I am looking at
submitting this product to a agency...

 Many transformer manufacturers claim they build to UL ...standards,
obviously, this is not considered approved, but are there

transformer houses that can manufacture transformers that are considered
recognized components under a program similar to a sign shop program, where
customers can request custom wound transformers that are covered under the
UL recognition ?


Thanks for any input,


Ken

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

ISN or Current probe method on telecommunication ports?

[Richard Lee]

Dear Colleague,

Does anybody have done any conducted emission test on telecommunication
ports per EN55022 1998 standard requirement?

Currently, we have performed a conducted emission test of our product on the
shielded telecom port by using ISN and current probe methods, and the
results of both tests are totally different.

With ISN method, the EUT failed the conducted emission on shielded telecom
port by 20 dB.  With current probe method, our product passed the conducted
test with good margin.

We don't know what is the theory behind the ISN and Current probe methods?
Can anybody explain to us or advise what we need to do to pass the conducted
emission test? Can the test lab accept the current probe method test data or
we have to meet both limits of voltage and current requirements that listed
in table 4 of CISPR. 22 1997 standard?

Our product used all shielded cables on telecom ports.  Per Clause 9.5.3.3 &
9.5.3.4 of CISPR. 22 1997, both methods are allowed for telecom port
testing.  

Any suggestions or feedback will be very appreciated.  

Thanks in advance!

Richard Lee
Compliance Engineer
--
Terawave Communications, Inc.
30680 Huntwood, Ave.
Hayward, CA  94544
Tel: 510-401-6590   Fax: 510-401-6628
www.terawave.com

Re: 2. 4 GHz cordless telephone, question of general interest

[Ken Javor]

Several years ago I went to warm up some peanut butter I kept in the fridge
so that it would spread easier.  I had not noticed or forgotten that the
(metallized) security wrap underneath the plastic lid had not completely
detached from the jar lip.  I got a spectacular light show right through the
opaque plastic lid.  Potentials induced on the remnant metal strips were
high enough to arc over...

--
>From: umbdenst...@sensormatic.com
>To: emc-p...@ieee.org
>Subject: RE: 2. 4 GHz cordless telephone, question of general interest
>Date: Mon, Apr 23, 2001, 9:49 AM
>

>
> I once warmed up some leftover take-out Chinese food in the take-out
> containers with the metal handle.  The laws of physics worked -- the handle
> burned the container.
>
> Water is apparently resonant at 2450 MHz, but metal also reacts to EM waves.
> Your dishes may have metallic compounds in the glazes or substrate.  This
> will definitely warm up the "fajita platter". :-)
>
> Don Umbdenstock
>
>
>> --
>> From:  Ken Javor[SMTP:ken.ja...@emccompliance.com]
>> Reply To:  Ken Javor
>> Sent:  Monday, April 23, 2001 9:50 AM
>> To:  dinst...@uk.xyratex.com
>> Cc:  emc-p...@ieee.org
>> Subject:  Re: 2. 4 GHz cordless telephone, question of general
>> interest
>>
>>
>> Microwave safe dishes do not heat if put in an oven without food on them
>> to
>> heat by conduction; "melmac" cannot be pt in a microwave because it does
>> absorb - I don't know what's in melmac but it must have some water content
>> that does absorb energy.  Maybe the same goes for your pottery.  It's
>> REALLY
>> hazy, chemistry was one of my worst subjects, but some compounds have a
>> structure where they are bound to H2O molecules as in CaCO3*H2O (I just
>> made
>> up that combination for illustration).  Such a compound could be
>> completely
>> "dry" but still retain H2O content.  This is purely supposition on my
>> part.
>>
>> --
>> >From: david_inst...@uk.xyratex.com (David Instone)
>> >To: Ken Javor 
>> >Cc: emc-p...@ieee.org
>> >Subject: Re: 2. 4 GHz cordless telephone, question of general interest
>> >Date: Mon, Apr 23, 2001, 3:05 AM
>> >
>>
>> > Ken Javor wrote:
>> >>
>> >> Just goes to show you can find anything on the net.  I have measured
>> leakage
>> >> from microwave ovens and every one was at 2450 MHz.  And that IS a
>> resonant
>> >> frequency for water and water alone.  That's why you can put waterless
>> items
>> >> in and they won't heat up,
>> >
>> > Hm, now I wonder how the the totally dry and empty pottery plate I put
>> > in the microwave to heat (before I put my non microwave cooked food on
>> > it) gets too hot to hold after just 60 seconds at 650W.
>> >
>> >
>> >> and also why you should never run a microwave
>> >> oven without a water load: with no load you get high vswr and the
>> magnetron
>> >> can be damaged by reflected energy.
>> > --
>> > Regards
>> >
>> > Dave Instone. Compliance Engineer
>> >  Storage Systems Development, MP24/22
>> >  Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
>> > Tel: +44 (0)23-92-496862 (direct line)
>> > Fax: +44 (0)23-92-496014
>> > http://www.xyratex.com  Tel: +44 (0)23-92-496000
>> >
>>
>> ---
>> This message is from the IEEE EMC Society Product Safety
>> Technical Committee emc-pstc discussion list.
>>
>> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>>
>> To cancel your subscription, send mail to:
>>  majord...@ieee.org
>> with the single line:
>>  unsubscribe emc-pstc
>>
>> For help, send mail to the list administrators:
>>  Michael Garretson:pstc_ad...@garretson.org
>>  Dave Healddavehe...@mediaone.net
>>
>> For policy questions, send mail to:
>>  Richard Nute:   ri...@ieee.org
>>  Jim Bacher: j.bac...@ieee.org
>>
>> All emc-pstc postings are archived and searchable on the web at:
>> http://www.rcic.com/  click on "Virtual Conference Hall,"
>>
>
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
>
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>
> To cancel your subscription, send mail to:
>  majord...@ieee.org
> with the single line:
>  unsubscribe emc-pstc
>
> For help, send mail to the list administrators:
>  Michael Garretson:pstc_ad...@garretson.org
>  Dave Healddavehe...@mediaone.net
>
> For policy questions, send mail to:
>  Richard Nute:   ri...@ieee.org
>  Jim Bacher: j.bac...@ieee.org
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.rcic.com/  click on "Virtual Conference Hall,"
> 

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subsc

Re: 2. 4 GHz cordless telephone, question of general interest

[Ken Javor]

RAM absorbs rf energy by virtue of a controlled conductivity via impregnated
carbon, but it is a broadband effect, just as you state.  2450 MHz is the
frequency which excites vibration in H2O molecules, so H2O is PARTICULARLY
efficient at absorbing energy at that frequency.  Certainly other media may
absorb the energy as well, but at greatly reduced efficiency relative to
H2O.  Pure distilled H2O will resonate at 2450 MHz.  It is not the
impurities in the water which cause the effect, but the nature of the polar
H2O molecule itself.

--
>From: Cortland Richmond <72146@compuserve.com>
>To: David Instone , ieee pstc list

>Subject: Re: 2. 4 GHz cordless telephone, question of general interest
>Date: Mon, Apr 23, 2001, 9:35 AM
>

>
> A lump of coal will heat up in a microwave oven. No water needed. It is the
> bulk resistivity of an object which allows circulating currents to generate
> heat, and while water can help (when we wet something, its chemical bonds
> are a source of electrons) it is not the only thing that is heated in a
> microwave oven.
>
> The cones from our chambers don't have water in them (better not, anyway)
> and they'll not only heat up in the microwave, but burn with a nasty, nasty
> smell. The carbon conducts, the foam that holds it burns. Not to denigrate
> water's action; I remember reading that a serviceable Radar Absorbing
> Material may be made by wetting foam urethane. But the frequency of
> microwave ovens wasn't chosen for resonance with water.
>
> (PURE, distilled water is an insulator. I wonder if 2450 is close enough to
> even warm it up?)
>
> Cortland
>
>
> == Original Message Follows 
>
>  >> Date:  23-Apr-01 02:07:07  MsgID: 1078-34037  ToID: 72146,373
> From:  David Instone >INTERNET:david_inst...@uk.xyratex.com
> Subj:  Re: 2. 4 GHz cordless telephone, question of general interest
> Chrg:  $0.00   Imp: Norm   Sens: StdReceipt: NoParts: 1
>
> Date: Mon, 23 Apr 2001 09:05:38 +0100
> From: david_inst...@uk.xyratex.com (David Instone)
> Subject: Re: 2. 4 GHz cordless telephone, question of general interest
> Reply-To: david_inst...@uk.xyratex.com (David Instone)
>
>
> Ken Javor wrote:
>>
>> Just goes to show you can find anything on the net.  I have measured
> leakage
>> from microwave ovens and every one was at 2450 MHz.  And that IS a
> resonant
>> frequency for water and water alone.  That's why you can put waterless
> items
>> in and they won't heat up,
>
> Hm, now I wonder how the the totally dry and empty pottery plate I put
> in the microwave to heat (before I put my non microwave cooked food on
> it) gets too hot to hold after just 60 seconds at 650W.
>
>
>> and also why you should never run a microwave
>> oven without a water load: with no load you get high vswr and the
> magnetron
>> can be damaged by reflected energy.
> --
> Regards
>
> Dave Instone. Compliance Engineer
>  Storage Systems Development, MP24/22
>  Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
> Tel: +44 (0)23-92-496862 (direct line)
> Fax: +44 (0)23-92-496014
> http://www.xyratex.com  Tel: +44 (0)23-92-496000
>
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
>
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>
> To cancel your subscription, send mail to:
>  majord...@ieee.org
> with the single line:
>  unsubscribe emc-pstc
>
> For help, send mail to the list administrators:
>  Michael Garretson:pstc_ad...@garretson.org
>  Dave Healddavehe...@mediaone.net
>
> For policy questions, send mail to:
>  Richard Nute:   ri...@ieee.org
>  Jim Bacher: j.bac...@ieee.org
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.rcic.com/  click on "Virtual Conference Hall,"
>
>
>
> **Primary Recipient:
>   Ken Javor INTERNET:ken.ja...@emccompliance.com
>
> == End of Original Message =
>
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
>
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
>
> To cancel your subscription, send mail to:
>  majord...@ieee.org
> with the single line:
>  unsubscribe emc-pstc
>
> For help, send mail to the list administrators:
>  Michael Garretson:pstc_ad...@garretson.org
>  Dave Healddavehe...@mediaone.net
>
> For policy questions, send mail to:
>  Richard Nute:   ri...@ieee.org
>  Jim Bacher: j.bac...@ieee.org
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.rcic.com/  click on "Virtual Conference Hall,"
> 

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

RE: Transformer Question

[Gary McInturff]

Usually, you have to submit an "unpotted transform" and while not a
big deal it takes extra co-ordination with the transformer folks. A more
important feature, at least for me, is that the vendor has to prove all of
the materials and thicknesses, not me. It also allows the manufacturer of
the transformer to make cost changes to the transformer by either submitting
the changes directly the safety house, and not impacting my delivery
schedule.
Gary

-Original Message-
From: Peter Merguerian [mailto:pmerguer...@itl.co.il]
Sent: Monday, April 23, 2001 3:00 AM
To: 'Matsuda, Ken'; emc-p...@ieee.org
Subject: RE: Transformer Question



Ken,

The closest you can get is UL's category for Transformers (Construction
Only) and covered under their category XORU2. These are teransformers that
have been cosntructed to various standards and meet the constructional
requirements only. Testing is done as part of the end-product. 

It is a benefit to have coverage under this category since it would
alleviate from submitting transformers and parts list for dissection and
construction evaluation. Dissecting a transfrormer is the last thing a
product safety engineer wishes to touch! Agree?




PETER S. MERGUERIAN
Technical Director
I.T.L. (Product Testing) Ltd.
26 Hacharoshet St., POB 211
Or Yehuda 60251, Israel
Tel: 972-3-5339022  Fax: 972-3-5339019
Mobile: 972-54-838175






-Original Message-
From: Matsuda, Ken [mailto:matsu...@curtisinst.com]
Sent: Saturday, April 21, 2001 1:38 AM
To: emc-p...@ieee.org
Subject: Transformer Question



Group,

I was wondering if you could help me with this one?  Currently, I have a
switching power supply, using custom transformers. Now I am looking at
submitting this product to a agency...

 Many transformer manufacturers claim they build to UL ...standards,
obviously, this is not considered approved, but are there

transformer houses that can manufacture transformers that are considered
recognized components under a program similar to a sign shop program, where
customers can request custom wound transformers that are covered under the
UL recognition ?


Thanks for any input,


Ken

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: ESD generators max Contact discharge level

[Price, Ed]

>-Original Message-
>From: Chris Maxwell [mailto:chris.maxw...@gnnettest.com]
>Sent: Monday, April 23, 2001 4:45 AM
>To: 'Dan Kinney (A)'; Douglas C. Smith; Terry Meck
>Cc: emc-p...@ieee.org
>Subject: RE: ESD generators max Contact discharge level
>
>
>
>Hi Dan,
>
>Air discharges are made anywhere on the product where an 
>insulator covers
>possibly sensitive features.  
>
>Membrane keypads are a great example.  The keypads contain traces and
>circuitry that may be sensitive to ESD.  However, since the 
>outermost layer
>is an insulator, making a contact discharge would not be a 
>real world test.
>I believe that it may also damage the contact discharge relay 
>in certain ESD
>generators.   I can explain that in more detail if you would 
>like.  In my
>experience, membrane keypads are always tested with air discharge.
>

SNIP

>
>Chris Maxwell
>Design Engineer
>NetTest
>6 Rhoads Drive, Building 4
>Utica,NY 13502
>email: chris.maxw...@gnnettest.com
>phone:  315-266-5128
>fax: 315-797-8024
>

Chris:

I don't understand why a membrane switchpad would not be tested for contact
discharge. It think that this is the absolutely most likely place where a
finger, attached to a charged human body, might be applied to the EUT. It
seems to me that you would want to be testing the dielectric strength of the
insulation over the keypad conductive traces.

The issue of whether a triggering of the testing gun, without a completed
discharge current, would damage the gun, isn't relevant to the need for the
test. Dumping 15 or 20 kV to a probe tip, while not exactly trivial, still
shouldn't be critically sensitive to load conditions. 

Regards,

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 Services Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: 2. 4 GHz cordless telephone, question of general interest

[UMBDENSTOCK]

I once warmed up some leftover take-out Chinese food in the take-out
containers with the metal handle.  The laws of physics worked -- the handle
burned the container.  

Water is apparently resonant at 2450 MHz, but metal also reacts to EM waves.
Your dishes may have metallic compounds in the glazes or substrate.  This
will definitely warm up the "fajita platter". :-)

Don Umbdenstock


> --
> From: Ken Javor[SMTP:ken.ja...@emccompliance.com]
> Reply To: Ken Javor
> Sent: Monday, April 23, 2001 9:50 AM
> To:   dinst...@uk.xyratex.com
> Cc:   emc-p...@ieee.org
> Subject:  Re: 2. 4 GHz cordless telephone, question of general
> interest
> 
> 
> Microwave safe dishes do not heat if put in an oven without food on them
> to
> heat by conduction; "melmac" cannot be pt in a microwave because it does
> absorb - I don't know what's in melmac but it must have some water content
> that does absorb energy.  Maybe the same goes for your pottery.  It's
> REALLY
> hazy, chemistry was one of my worst subjects, but some compounds have a
> structure where they are bound to H2O molecules as in CaCO3*H2O (I just
> made
> up that combination for illustration).  Such a compound could be
> completely
> "dry" but still retain H2O content.  This is purely supposition on my
> part.
> 
> --
> >From: david_inst...@uk.xyratex.com (David Instone)
> >To: Ken Javor 
> >Cc: emc-p...@ieee.org
> >Subject: Re: 2. 4 GHz cordless telephone, question of general interest
> >Date: Mon, Apr 23, 2001, 3:05 AM
> >
> 
> > Ken Javor wrote:
> >>
> >> Just goes to show you can find anything on the net.  I have measured
> leakage
> >> from microwave ovens and every one was at 2450 MHz.  And that IS a
> resonant
> >> frequency for water and water alone.  That's why you can put waterless
> items
> >> in and they won't heat up,
> >
> > Hm, now I wonder how the the totally dry and empty pottery plate I put
> > in the microwave to heat (before I put my non microwave cooked food on
> > it) gets too hot to hold after just 60 seconds at 650W.
> >
> >
> >> and also why you should never run a microwave
> >> oven without a water load: with no load you get high vswr and the
> magnetron
> >> can be damaged by reflected energy.
> > --
> > Regards
> >
> > Dave Instone. Compliance Engineer
> >  Storage Systems Development, MP24/22
> >  Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
> > Tel: +44 (0)23-92-496862 (direct line)
> > Fax: +44 (0)23-92-496014
> > http://www.xyratex.com  Tel: +44 (0)23-92-496000
> > 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
> 
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
> 
> To cancel your subscription, send mail to:
>  majord...@ieee.org
> with the single line:
>  unsubscribe emc-pstc
> 
> For help, send mail to the list administrators:
>  Michael Garretson:pstc_ad...@garretson.org
>  Dave Healddavehe...@mediaone.net
> 
> For policy questions, send mail to:
>  Richard Nute:   ri...@ieee.org
>  Jim Bacher: j.bac...@ieee.org
> 
> All emc-pstc postings are archived and searchable on the web at:
> http://www.rcic.com/  click on "Virtual Conference Hall,"
> 

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: ESD generators max Contact discharge level

[Cortland Richmond]

Since the contact method requires penetrating thin, cosmetic coatings, it
is a bad idea on membrane keypads; bore that sharp point into the  contacts
and it's ruined even before you hit the electronics. Not that they'd fare
all that well with direct discharge! In any case, there is often some more
properly accessible metal nearby.

Cortland

== Original Message Follows 

 >> Date:  23-Apr-01 04:49:02  MsgID: 1078-34050  ToID: 72146,373
From:  Chris Maxwell >INTERNET:chris.maxw...@gnnettest.com
Subj:  RE: ESD generators max Contact discharge level
Chrg:  $0.00   Imp: Norm   Sens: StdReceipt: NoParts: 1

From: Chris Maxwell 
Subject: RE: ESD generators max Contact discharge level
List-Post: emc-pstc@listserv.ieee.org
Date: Mon, 23 Apr 2001 07:44:41 -0400
Reply-To: Chris Maxwell 
 

Hi Dan,

Air discharges are made anywhere on the product where an insulator covers
possibly sensitive features.  

Membrane keypads are a great example.  The keypads contain traces and
circuitry that may be sensitive to ESD.  However, since the outermost layer
is an insulator, making a contact discharge would not be a real world test.
I believe that it may also damage the contact discharge relay in certain
ESD
generators.   I can explain that in more detail if you would like.  In my
experience, membrane keypads are always tested with air discharge.

There are other surfaces that offer more chance for interpretation and
debate. 

The main sticking point here is the definition of insulation.  Some people
try to consider paint on a metal surface as insulation.  In this case they
will only make air discharges to painted metal surfaces.  Others do not
consider the paint as an insulator, they will poke the contact discharge
tip
down through the paint until it gets to bare metal and then make contact
discharges.  The same question arises with insulating passivation
treatments
such as black anodize treatment on Aluminum.  Each product is different and
each coating is different, this is where the compliance engineer has to use
some honest judgement.  

My humble opinion is that I poke the tip through paints and passivation
coatings of metals to perform contact discharges.  If there is an actual
piece of material such as a plastic overlay over the metal; then I use air
discharge.

I have a non-compliance collegue here that used to work on military
projects. He has told me that there is a US military standard that actually
classifies different metal treatments such as passivation coatings, paints
and baked on enamels as "insulators" or not.  However, I have never found
this standard.  In its absence, I have used the rule of thumb above.

Chris Maxwell
Design Engineer
NetTest
6 Rhoads Drive, Building 4
Utica,NY 13502
email: chris.maxw...@gnnettest.com
phone:  315-266-5128
fax: 315-797-8024




> -Original Message-
> From: Dan Kinney (A) [SMTP:dan.kin...@heapg.com]
> Sent: Friday, April 20, 2001 6:07 PM
> To:   Douglas C. Smith; Terry Meck
> Cc:   emc-p...@ieee.org
> Subject:  RE: ESD generators max Contact discharge level
> 
> 
> While we're on the topic, I have a question (actually a couple) regarding
> air discharge.  Since contact discharge is the preferred method, as
stated
> in an earlier message and in EN61000-4-2, Paragraph 5, why would one
> perform
> the Air Discharge method?  The same paragraph states "Air discharges
shall
> be used where contact discharge cannot be applied."  What conditions
would
> make it such that contact discharge could not be applied?
> 
> Thanks in advance.
> Dan Kinney
> Horner APG
> 
> > -Original Message-
> > From:   Douglas C. Smith [SMTP:d...@emcesd.com]
> > Sent:   Friday, April 20, 2001 2:54 PM
> > To: Terry Meck
> > Cc: emc-p...@ieee.org
> > Subject:Re: ESD generators max Contact discharge level
> > 
> > 
> > Hi Terry and the group,
> > 
> > Besides the question of finding a generator that can reach the level
you
> > mention, I am not aware of any natural ESD event that approaches the
> > interference potential of even an 8 kV contact discharge. The problem
> > comes in that high voltage air discharges have relatively slow
> > risetimes, for 16 kV on the order of tens of ns, whereas contact
> > discharges maintain a better than 1 ns risetime at all voltages. This
> > makes for a much smaller dt to go along with the greater di to make a
> > di/dt that is much higher, more than an order of magnitude, than you
> > will see for these voltages in nature.
> > 
> > Maybe if you were making atom bomb trigger mechanisms there would be a
> > justification for this kind of testing, but not for real equipment.
> > 
> > On the other hand very low voltage (and energy) events, such as
jinjling
> > change have very high di/dt because of the tens of ps risetimes that
> > occur at low voltage. The combination of high voltage (and energy) with
> > fast risetimes is too severe and meeting such a test is a waste of
money
> > for most equipmen

Re: 2. 4 GHz cordless telephone, question of general interest

[Cortland Richmond]

A lump of coal will heat up in a microwave oven. No water needed. It is the
bulk resistivity of an object which allows circulating currents to generate
heat, and while water can help (when we wet something, its chemical bonds
are a source of electrons) it is not the only thing that is heated in a
microwave oven.

The cones from our chambers don't have water in them (better not, anyway)
and they'll not only heat up in the microwave, but burn with a nasty, nasty
smell. The carbon conducts, the foam that holds it burns. Not to denigrate
water's action; I remember reading that a serviceable Radar Absorbing
Material may be made by wetting foam urethane. But the frequency of
microwave ovens wasn't chosen for resonance with water.

(PURE, distilled water is an insulator. I wonder if 2450 is close enough to
even warm it up?)

Cortland


== Original Message Follows 

 >> Date:  23-Apr-01 02:07:07  MsgID: 1078-34037  ToID: 72146,373
From:  David Instone >INTERNET:david_inst...@uk.xyratex.com
Subj:  Re: 2. 4 GHz cordless telephone, question of general interest
Chrg:  $0.00   Imp: Norm   Sens: StdReceipt: NoParts: 1

List-Post: emc-pstc@listserv.ieee.org
Date: Mon, 23 Apr 2001 09:05:38 +0100
From: david_inst...@uk.xyratex.com (David Instone)
Subject: Re: 2. 4 GHz cordless telephone, question of general interest
Reply-To: david_inst...@uk.xyratex.com (David Instone)
 

Ken Javor wrote:
> 
> Just goes to show you can find anything on the net.  I have measured
leakage
> from microwave ovens and every one was at 2450 MHz.  And that IS a
resonant
> frequency for water and water alone.  That's why you can put waterless
items
> in and they won't heat up,

Hm, now I wonder how the the totally dry and empty pottery plate I put
in the microwave to heat (before I put my non microwave cooked food on
it) gets too hot to hold after just 60 seconds at 650W.


> and also why you should never run a microwave
> oven without a water load: with no load you get high vswr and the
magnetron
> can be damaged by reflected energy.
-- 
Regards

Dave Instone. Compliance Engineer
 Storage Systems Development, MP24/22
 Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
Tel: +44 (0)23-92-496862 (direct line)
Fax: +44 (0)23-92-496014
http://www.xyratex.com  Tel: +44 (0)23-92-496000

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"



**Primary Recipient:
  Ken Javor INTERNET:ken.ja...@emccompliance.com

== End of Original Message =

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

April, 2001 EMC/Telco/Product Safety Update Now Available

[Glen Dash]

The Curtis-Straus Update is for April, 2001 is now available at:

http://www.conformity-update.com

The headlinea are:

VATICAN RADIO TOWER SPARKS ITALIAN PROTEST.
CANADA SEEKS COMMENT ON CELL PHONE JAMMERS.
FCC AMENDS PART 15.
PRODUCER OF DEFECTIVE BATTERIES PLEADS GUILTY TO FRAUD.
EU STANDARDS UPDATE.
ANSI/IEC STANDARDS UPDATE.
MEETINGS, SEMINARS, ETC.

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

Re: 2. 4 GHz cordless telephone, question of general interest

[Ken Javor]

Microwave safe dishes do not heat if put in an oven without food on them to
heat by conduction; "melmac" cannot be pt in a microwave because it does
absorb - I don't know what's in melmac but it must have some water content
that does absorb energy.  Maybe the same goes for your pottery.  It's REALLY
hazy, chemistry was one of my worst subjects, but some compounds have a
structure where they are bound to H2O molecules as in CaCO3*H2O (I just made
up that combination for illustration).  Such a compound could be completely
"dry" but still retain H2O content.  This is purely supposition on my part.

--
>From: david_inst...@uk.xyratex.com (David Instone)
>To: Ken Javor 
>Cc: emc-p...@ieee.org
>Subject: Re: 2. 4 GHz cordless telephone, question of general interest
>Date: Mon, Apr 23, 2001, 3:05 AM
>

> Ken Javor wrote:
>>
>> Just goes to show you can find anything on the net.  I have measured leakage
>> from microwave ovens and every one was at 2450 MHz.  And that IS a resonant
>> frequency for water and water alone.  That's why you can put waterless items
>> in and they won't heat up,
>
> Hm, now I wonder how the the totally dry and empty pottery plate I put
> in the microwave to heat (before I put my non microwave cooked food on
> it) gets too hot to hold after just 60 seconds at 650W.
>
>
>> and also why you should never run a microwave
>> oven without a water load: with no load you get high vswr and the magnetron
>> can be damaged by reflected energy.
> --
> Regards
>
> Dave Instone. Compliance Engineer
>  Storage Systems Development, MP24/22
>  Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
> Tel: +44 (0)23-92-496862 (direct line)
> Fax: +44 (0)23-92-496014
> http://www.xyratex.com  Tel: +44 (0)23-92-496000
> 

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

Interference generator - data lines

Does anyone have information on Koepfer Model SG41 Interference Generator's
Option 1500, a capacitive-inductive coupling fixture?

The SG41/option 1500 injects interference into data lines under controlled
conditions. Koepfer's drawing shows parallel data and pulse lines of defined
length and separation, resulting in inductive-capacitive coupling.  Their
drawing is not dimensioned or toleranced.

The Koepfer SG41 is no longer on the market, but we could duplicate the 1500
coupling device if we knew the wire diameters, spacing and length.  

David Sterner
ADEMCO
165 Eileen Way
Syosset NY
516-921-6704 x6970
fax 516-364-6953

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

Re: Job Description

[georgea]

Luiz,

You can couch the following topics in whatever "buzz words" are in vogue
in your company, but I see the following list as the Product Safety "cycle"
of activities:

-  Understand the applicable global product safety design standards.
-  Establish any desirable company product safety policies/practices
   that exceed the global requirements.
-  Understand the applicable tests for proof of conformity
-  Understand individual country certification processes
-  Communicate requirements to those responsible for the design and/or
   certification processes (may be external to your company).
-  Review early and final designs for conformity to applicable standards.
-  Submit the product for the appropriate certifications, or monitor the process
   if not the actual applicant
-  Resolve or assist in resolving issues raised by certification bodies.
-  Ensure that all of the required certification documents are in place at the
   start of manufacture, including any agency FUS procdures.
-  Participate in resolving manufacturing and/or field issues as they arise.
-  Ensure that certifications are amended to reflect alternate components
   and/or manufacturing sites.
-  Use field performance as a measure of the soundness of the initial design
   parameters.
-  Be aware of any emerging significant changes to global requirements.
-  Factor all of the above into the requirements for the next product.


George Alspaugh
Lexmark International Inc.




"Luiz Claudio"  on 04/21/2001
08:28:36 AM

Please respond to "Luiz Claudio" 

To:   emc-pstc%ieee@interlock.lexmark.com
cc:(bcc: George Alspaugh/Lex/Lexmark)
Subject:  Job Description


Dear Colleagues,

I have been asked to write a complete new job description for a Product
Safety / Codes Compliance Engineer. Although being familiar with this
activity (I'm on it for almost 10 years), I would like to avoid describing
"my job", since this could lead to some kind of bias.
If any of you has a job description of a product safety engineer who is
responsible for getting compliance certifications of electrical products, I
would be very thankful for receiving it.
In order to avoid overflowing this list with attached files, I'd appreciate
receiving the responses through my personal email address.

Regards,

Luiz




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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

RE: ESD generators max Contact discharge level

[Chris Maxwell]

Hi Dan,

Air discharges are made anywhere on the product where an insulator covers
possibly sensitive features.  

Membrane keypads are a great example.  The keypads contain traces and
circuitry that may be sensitive to ESD.  However, since the outermost layer
is an insulator, making a contact discharge would not be a real world test.
I believe that it may also damage the contact discharge relay in certain ESD
generators.   I can explain that in more detail if you would like.  In my
experience, membrane keypads are always tested with air discharge.

There are other surfaces that offer more chance for interpretation and
debate. 

The main sticking point here is the definition of insulation.  Some people
try to consider paint on a metal surface as insulation.  In this case they
will only make air discharges to painted metal surfaces.  Others do not
consider the paint as an insulator, they will poke the contact discharge tip
down through the paint until it gets to bare metal and then make contact
discharges.  The same question arises with insulating passivation treatments
such as black anodize treatment on Aluminum.  Each product is different and
each coating is different, this is where the compliance engineer has to use
some honest judgement.  

My humble opinion is that I poke the tip through paints and passivation
coatings of metals to perform contact discharges.  If there is an actual
piece of material such as a plastic overlay over the metal; then I use air
discharge.

I have a non-compliance collegue here that used to work on military
projects. He has told me that there is a US military standard that actually
classifies different metal treatments such as passivation coatings, paints
and baked on enamels as "insulators" or not.  However, I have never found
this standard.  In its absence, I have used the rule of thumb above.

Chris Maxwell
Design Engineer
NetTest
6 Rhoads Drive, Building 4
Utica,NY 13502
email: chris.maxw...@gnnettest.com
phone:  315-266-5128
fax: 315-797-8024




> -Original Message-
> From: Dan Kinney (A) [SMTP:dan.kin...@heapg.com]
> Sent: Friday, April 20, 2001 6:07 PM
> To:   Douglas C. Smith; Terry Meck
> Cc:   emc-p...@ieee.org
> Subject:  RE: ESD generators max Contact discharge level
> 
> 
> While we're on the topic, I have a question (actually a couple) regarding
> air discharge.  Since contact discharge is the preferred method, as stated
> in an earlier message and in EN61000-4-2, Paragraph 5, why would one
> perform
> the Air Discharge method?  The same paragraph states "Air discharges shall
> be used where contact discharge cannot be applied."  What conditions would
> make it such that contact discharge could not be applied?
> 
> Thanks in advance.
> Dan Kinney
> Horner APG
> 
> > -Original Message-
> > From:   Douglas C. Smith [SMTP:d...@emcesd.com]
> > Sent:   Friday, April 20, 2001 2:54 PM
> > To: Terry Meck
> > Cc: emc-p...@ieee.org
> > Subject:Re: ESD generators max Contact discharge level
> > 
> > 
> > Hi Terry and the group,
> > 
> > Besides the question of finding a generator that can reach the level you
> > mention, I am not aware of any natural ESD event that approaches the
> > interference potential of even an 8 kV contact discharge. The problem
> > comes in that high voltage air discharges have relatively slow
> > risetimes, for 16 kV on the order of tens of ns, whereas contact
> > discharges maintain a better than 1 ns risetime at all voltages. This
> > makes for a much smaller dt to go along with the greater di to make a
> > di/dt that is much higher, more than an order of magnitude, than you
> > will see for these voltages in nature.
> > 
> > Maybe if you were making atom bomb trigger mechanisms there would be a
> > justification for this kind of testing, but not for real equipment.
> > 
> > On the other hand very low voltage (and energy) events, such as jinjling
> > change have very high di/dt because of the tens of ps risetimes that
> > occur at low voltage. The combination of high voltage (and energy) with
> > fast risetimes is too severe and meeting such a test is a waste of money
> > for most equipment.
> > 
> > Doug
> > 
> > Terry Meck wrote:
> > > 
> > > Hello again:
> > > 
> > > Does anyone recall if there were any standard called for or ESD
> > generator that simulated as the case may be =>  +-10 kV CONTACT
> discharge.
> > > 
> > > We have a customer that is specifying passing +-16 kV ESD without
> > referring to AIR or Contact discharge.  I am inclined to ask what they
> > have in mind since I have not seen any generators that go that high in
> the
> > Contact mode.
> > > I suspect the writer of the SOW knows nothing and the engineering
> group
> > only thinks Air Discharge.
> > > 
> > > What do you all think?
> > > 
> > > Terry J. Meck
> > > Accu-Sort Systems Inc.
> > > 
> > > ---
> > > This message is from the IEEE EMC Society Product Safety
> > > Technical Committee emc-pstc 

RE: Transformer Question

[Peter Merguerian]

Ken,

The closest you can get is UL's category for Transformers (Construction
Only) and covered under their category XORU2. These are teransformers that
have been cosntructed to various standards and meet the constructional
requirements only. Testing is done as part of the end-product. 

It is a benefit to have coverage under this category since it would
alleviate from submitting transformers and parts list for dissection and
construction evaluation. Dissecting a transfrormer is the last thing a
product safety engineer wishes to touch! Agree?




PETER S. MERGUERIAN
Technical Director
I.T.L. (Product Testing) Ltd.
26 Hacharoshet St., POB 211
Or Yehuda 60251, Israel
Tel: 972-3-5339022  Fax: 972-3-5339019
Mobile: 972-54-838175






-Original Message-
From: Matsuda, Ken [mailto:matsu...@curtisinst.com]
Sent: Saturday, April 21, 2001 1:38 AM
To: emc-p...@ieee.org
Subject: Transformer Question



Group,

I was wondering if you could help me with this one?  Currently, I have a
switching power supply, using custom transformers. Now I am looking at
submitting this product to a agency...

 Many transformer manufacturers claim they build to UL ...standards,
obviously, this is not considered approved, but are there

transformer houses that can manufacture transformers that are considered
recognized components under a program similar to a sign shop program, where
customers can request custom wound transformers that are covered under the
UL recognition ?


Thanks for any input,


Ken

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"

Re: 2. 4 GHz cordless telephone, question of general interest

[David Instone]

Ken Javor wrote:
> 
> Just goes to show you can find anything on the net.  I have measured leakage
> from microwave ovens and every one was at 2450 MHz.  And that IS a resonant
> frequency for water and water alone.  That's why you can put waterless items
> in and they won't heat up,

Hm, now I wonder how the the totally dry and empty pottery plate I put
in the microwave to heat (before I put my non microwave cooked food on
it) gets too hot to hold after just 60 seconds at 650W.


> and also why you should never run a microwave
> oven without a water load: with no load you get high vswr and the magnetron
> can be damaged by reflected energy.
-- 
Regards

Dave Instone. Compliance Engineer
 Storage Systems Development, MP24/22
 Xyratex, Langstone Rd., Havant, Hampshire, P09 1SA, UK.
Tel: +44 (0)23-92-496862 (direct line)
Fax: +44 (0)23-92-496014
http://www.xyratex.com  Tel: +44 (0)23-92-496000

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

Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/

To cancel your subscription, send mail to:
 majord...@ieee.org
with the single line:
 unsubscribe emc-pstc

For help, send mail to the list administrators:
 Michael Garretson:pstc_ad...@garretson.org
 Dave Healddavehe...@mediaone.net

For policy questions, send mail to:
 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/  click on "Virtual Conference Hall,"