RE: metallic coatings

[Wani, Vijay (V)]

Ken:
You might try to make the plastic housing/box itself out of a conductive
composite. We have some polymer composites which can be injection molded, and
which shield to high levels. This would get around having to redesign the
circuit and also some of the problems you cite with coatings (peeling, etc).
Any interest in this?

Vijay Wani
The Dow Chemical Company
Office (989) 636-0473   
Fax (989)638-9289
vw...@dow.com



From: Joseph Randolph [mailto:j...@randolph-telecom.com]
Sent: Thursday, October 16, 2003 11:37 PM
To: 'Ken Javor'; emc-p...@majordomo.ieee.org
Subject: RE: metallic coatings



Hi Ken:

Conductive coatings are tricky, and I generally try to avoid them.  It
can be difficult to get good electrical connections at the separations
where different parts of the box meet, unless the mating surfaces have
been specifically designed for the purpose.  Even so, the contact
quality can deteriorate over time with some materials.  Worse yet, some
coatings have a tendency to peel as they age.  I would think these
limitations would be even more of an issue for military environmental
conditions.

I don't know the background of your request, but if this is being
contemplated as a band-aid for an EMC problem, you may want to pursue
other fixes such as circuit board revisions.

If you really do need some shielding but want to avoid the coatings, you
might consider a stamped steel insert made out of thin sheet metal that
conforms to the inside contours of the plastic box.  There are also some
shielding constructions where a conductive film is bonded to a
non-conductive substrate that can be die stamped and then folded to fit
around the circuit board inside the plastic housing.

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


> -Original Message-
> From: owner-emc-p...@majordomo.ieee.org 
> [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ken Javor
> Sent: Thursday, October 16, 2003 10:03 PM
> To: emc-p...@majordomo.ieee.org
> Subject: metallic coatings
> 
> 
> 
> Does anyone have any suggestions for a metallic coating that 
> can be deposited on the interior of a plastic box that would 
> need to meet military environmental conditions?  Suggestions 
> for other metallization techniques are also welcome.
> 
> Thank you. 
> 
> 
> ---
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Flat panel display monitor base holder

[Wani, Vijay (V)]

Hello:
is there any safety/EMC reason for having metal structure in flat panel
display monitor base holder?

thank you in advance.

vijay wani
989-636-0473


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Fuel cell product and EMC

[Wani, Vijay (V)]

Hello Group:
is there any special EMC related requirement specific to fuel cell products?

thank you in advance.
vijay wani
Dow Chemical


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RE: Fire Retardants

[Wani, Vijay (V)]

specimens are to be preconditioned for flammability (94 V0, V1 & V2) testing. 
1.  two sets of five specimens each are to be preconditioned in accordance 
with
ASTM D618 at 23 C, 50 RH for 48 hours.
2.  two sets of five specimens each are to be preconditioned in an
air-circulating oven for 168 hours at 70 C and then cooled in desiccator for
at least 4 hours at room temp prior to testing. (as an alternative, industrial
laminates may be conditioned for 24 hours at 125 C.)

hope this helps.

vijay wani
Dow Chemical



From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com]
Sent: Tuesday, March 18, 2003 1:57 PM
To: richwo...@tycoint.com; emc-p...@majordomo.ieee.org
Subject: RE: Fire Retardants



Richard, I think that is one of the reason that the flame tests require aging
in ovens before UL et al burn them, but I don't know for certain.
Gary


From: richwo...@tycoint.com [mailto:richwo...@tycoint.com]
Sent: Tuesday, March 18, 2003 6:32 AM
To: emc-p...@majordomo.ieee.org
Subject: Fire Retardants



If a plastic containing a fire retardant is subjected to high heat (for
example, due to a overheated component) for an extended period of time (many
hours or several days), is it possible that the fire retardant in the
plastic will outgas sufficiently to decrease the flame rating of the plastic
in the heated area?

Richard Woods
Sensormatic Electronics
Tyco International



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EIA Standard of environment protect

[Wani, Vijay (V)]

Hello Group:
How can i get some information on EIA standard of environment protect?
thank you in advance.
vijay 


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ITE standard

[Wani, Vijay (V)]

Group: 
I am looking for ITE standard (UL or any other) for maximum allowable
exhaust air temperature from information technology equipment?

thank you in advance.

vijay wani

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CE (EN5013)

[Wani, Vijay (V)]

Group:
I am looking for CE(EN5013) standard. I will appreciate any help or
direction. 
thank you in advance.

vijay wani
The Dow Chemical Company
989-636-0473

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FCC Gives TV Makers Deadline

[Wani, Vijay (V)]

Group:
there was an article on wall-street journal about government's significant
attempts to speed the nation's changeover to digital television. does this
mean, digital TV has to comply with FCC Class B?

thank you in advance.

vijay wani


http://www.fcc.gov/headlines.html

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vibration test system

[Wani, Vijay (V)]

hello Group:
I am planing to buy vibration / shock test system for our lab. and
basically, looking for Vibration Research, Ling Dynamic System (LDS) and
Unholtz Dickie Corp. for the system (electrodynamic shaker, controller,
analyzer). I would appreciate any input / recommendation / experience on
vibration test system for their performance.

thank you in advance.

vijay wani
(989)636-0473 

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[no subject]

[Wani, Vijay (V)]

Thank you all for your valuable input. i apologize for late reply. i ordered
a copy of EN60950:2000. (thanks, Chris, George and constantin) and now, it
is getting much clearer. however, i have some questions and would appreciate
any comment.

as per EN60950:2000, 4.7.2.1: 
1.  Except where method 2 of 4.7.1 is used exclusively, or as permitted
in 4.7.2.2, the following parts are considered to have a risk of ignition
and, therefore, require a FIRE ENCLOSURE:
- components in PRIMARY CIRCUITS;

So if i am interpreting Rich and Scott's e-mail right (great explanation),
i do not need FIRE ENCLOSURE, if primary circuit is supplied by a Limited
Power source.   For an existing device, how do i know whether the primary
circuit is supplied by a Limited Power source?  are cell-phones, PDA's
typically supplied by Limited Power Source?

as per 4.7.3.4
2.  Inside FIRE ENCLOSURE, materials for components and other parts,
(including MECHANICAL and ELECTRICAL ENCLOSURE located inside FIRE
ENCLOSURS) shall comply with on of the following:
- be of FLAMMABILITY CLASS V-2 OR FLAMMABILITY CLASS HF-2; OR
- pass the flammability test described in clause A.2; or
- meet flammability requirements of a relevant IEC component standard which
includes such requirements.

Does this mean; if i have an enclosure inside a FIRE ENCLOSURE, than it has
to be V-2 eventhough there are no safety hazards resulting from complete
disapperance of the enclosure?

thank you.

vijay wani

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EMI radiated emissions

[Wani, Vijay (V)]

Group:

is there any resource where I can find radiated emissions data of various
electronics equipments (handhelds, laptops etc.)? I have seen the web-sites,
where they compare various Handhelds, Laptops etc. however nothing on emi
emissions.  I would apprecite any direction.

thank you in advance.

Vijay Wani

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radiated emission from 15 inch TFT-LCD

[Wani, Vijay (V)]

hello Group:

My question is kind of general but i would appreciate any input /
experience.
 typical, TFT-LCD is enclosed in a metal enclosure and there is a shielded
window to prevent any emi from front. Is LCD (video signal) big source of
emi?  if LCD unit not properly isolated (shielded) within a system, does it
immune to emi  (intra-system interference)?

thank you in advance.

vijay

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UL 60

[Wani, Vijay (V)]

Group:

What is UL 60? How can i get a copy of that standard? i searched on UL web
site but could not find it.

thank you in advance.

vijay



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e-display

[Wani, Vijay (V)]

hello Group:

I am working on e-display (number of LCD screens with its own digital
storage and processing). What safety and EMC standards apply to such device?
what category does that device fall under for EMC?

Thank you in advance.

Vijay Wani
The Dow Chemical Company
(989)-636-0473



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[no subject]

[Wani, Vijay (V)]

Check on following sheet manufacturers. i am not sure about EU.

Allen Extruders Inc.
www.allenx.com

Alltrista Corp.
www.alltrista.com

Budd Co.
www.buddcompany.com

DSM Engineering Plastic Products
www.dsmepp.com

Klockner Pentaplast of america inc.
www.klockner.com

O'sullivan corp.
www.osul.com

Plastic Suppliers Inc.
www.plasticsuppliers.com

Primex Plastics Corp.
www.primexplastics.com

Solvay SA
www.solvay.com

Spartech Corp
www.spartech.com


Vijay Wani
The Dow Chemical Company
* Office (989) 636-0473   Mobile (989) 859-0451
* Fax (989)638-9289
*vw...@dow.com



-Original Message-
From: Kim Boll Jensen [mailto:kimb...@post7.tele.dk]
Sent: Tuesday, January 15, 2002 6:03 AM
To: EMC-PSTC
Subject: UL Plastic


Hi all

I need a EU manufacturer or distributor of HD PE plastic in sheets with
UL 94HB approval as minimum.

My problem is that the UL database register gives me nearly only PE
pellets manufacturers not sheets. So I need to find the manufacturers of
the sheets who is using the UL approved pellets.

Can some one help me or point me in the right direction.

Best regards,


Kim Boll Jensen


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UL 60950 - safety related question

[Wani, Vijay (V)]

hello Group:

i have 8 LCD displays inside a box. if there is an outer metal enclosure,
does internal enclosure (which is plastic at each LCD display) need to be
V-0, does it need an RTI above the operation temperature? where should i
find guideline about V-0 and RTI requirements for particular equipment?

i would appreciate any response.

thank you in advance.

vijay Wani
989-636-0473
Dow Chemical

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[SI-LIST] multi-band devices

[Wani, Vijay (V)]

Hello Group:

I have a question regarding multi-band devices. How can I characterize
materials (shielded enclosure and other components in the enclosure) for
absorption of certain RF?

thank you in advance.

vijay wani

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RE: [SI-LIST] Re: emi shielding

[Wani, Vijay (V)]

all:thanks for your time and response.

I understand the frequency range we worry about (30MHz - 2GHz), any metal
(or metallized plastic) would be overkill and effect of apertures will be
mostly determing factor for shielding effectiveness.
but, the shielding mechanism of conductive metals (or metallized plastics)
is mostly reflective rather than absorbtion. 

 if we have a meterial with absorbtion shielding mechanism (in 30 MHz-2GHz
frequency range), is there any advantage? i would guess, that will reduce
antenna effect in the system. would appreciate any thoughts.

vijay wani
Dow Chemical

-Original Message-
From: Pettit, Ghery [mailto:ghery.pet...@intel.com]
Sent: Friday, November 09, 2001 12:14 PM
To: 'Wani, Vijay (V)'; 'emc-p...@majordomo.ieee.org';
'si-l...@freelists.org'
Subject: [SI-LIST] Re: emi shielding


Vijay,

The relative proportions are a function of frequency and the relative
conductivity and relative permittivity of the material.

The attached file is from a MathCAD 7.0 model that I put together a while
back.  The equations came from a Technit design guide published about 20
years ago.

You will note that in the frequency range that we usually worry about almost
any metal you might use is overkill.  It is the apertures that create the
problems.  The example in the document is copper.

I hope this helps.

Ghery Pettit, NCE



-----Original Message-
From: Wani, Vijay (V) [mailto:vw...@dow.com]
Sent: Friday, November 09, 2001 7:36 AM
To: 'emc-p...@majordomo.ieee.org'; 'si-l...@freelists.org'
Subject: emi shielding



hello:

as we know, threre are two main component of shielding effectiveness.
(Absorbtion and Reflection). is there any way to find out.. what percentage
of overall shielding is due to absorbtion / reflection for a given material?

thank you in advance.

Vijay Wani
Dow Chemical

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emi shielding

[Wani, Vijay (V)]

hello:

as we know, threre are two main component of shielding effectiveness.
(Absorbtion and Reflection). is there any way to find out.. what percentage
of overall shielding is due to absorbtion / reflection for a given material?

thank you in advance.

Vijay Wani
Dow Chemical

---
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Technical Committee emc-pstc discussion list.

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 unsubscribe emc-pstc

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 Dave Healddavehe...@mediaone.net

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vibration & shock testing

[Wani, Vijay (V)]

hello:

does anyone know ..
1. standard for vibration & shock testing (especially small hand held
electronic devices like cell phone, pda, laptop)?
2. any test lab who does such testing?
how common is such testing?

thank you in advance.

Vijay Wani


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RE: STP vs FTP Ethernet cables (2)

[Wani, Vijay (V)]

hello:
i am just curisous..how to measure shielding effectiveness of cables.. 
is shielding effectiveness of individual wire is better vs overall shield? 
is there any other ways to shield a cable? other than aluminium foil or
conductive fabric around the cable?
thank you in advance.

Vijay Wani
The Dow Chemical Company 
433 Building
Midland, MI 48667
Phone: 989-636-0473 Fax: 989-636-8785
Cell-phone: 517-859-0451



-Original Message-
From: Allan, James [mailto:james_al...@milgo.com]
Sent: Friday, September 07, 2001 9:04 AM
To: 'Paolo Roncone'
Cc: emc-p...@majordomo.ieee.org
Subject: RE: STP vs FTP Ethernet cables (2)



Paolo:  Try this link to Quabbin wire company.  It is a product selector
guide with the types of wire used for different applications.  All Ethernet
applications are 100 ohm characteristic impedance and only have overall
shields if shielded. Telecom cable (T1, DSL etc.) if shielded, are also 100
ohm but the shield (if present) is over the individual wire pairs with no
overall shield. I find no reference to standard Ethernet cable at 150 ohms.

LINK http://www.quabbin.com/finder/finder.cgi?cmd=app_form

Jim Allan
Manager, Engineering Services
Nextira Solutions LLC
1619 N Harrison Parkway
Sunrise, FL, 33323
E-mail james_al...@milgo.com
Phone (954) 846-3720
Fax (954) 846-6282

> -Original Message-
> From: Paolo Roncone [SMTP:pronc...@cisco.com]
> Sent: Friday, September 07, 2001 5:28 AM
> To:   "Meunier, Éric"
> Cc:   emc-p...@majordomo.ieee.org
> Subject:  RE: STP vs FTP Ethernet cables (2)
> 
> Eric,
> 
> this 150 ohm story of STP cables sounds completely new to me. Also, my
> understanding is that both UTP and STP are used for 10bT ethernet.
> In the STP definition of IEEE802.3, there is no mention about different
> characteristic impedances from the required 100ohm of 10bT.
> Unfortunately I haven't yet received an answer to my original question as
> to how STP cables should be actually made (shielded twisted pairs vs
> overall shield) .
> As I already said in previous e-mails, the "STP" cables that I got look
> pretty much the same as "FTP" cables, that is they have just an overall
> shield (aluminum foil) around all wires. And they are all declared to be
> 100 ohms.
> 
> Paolo
> 
> 
> At 16:56 06/09/2001 -0400, you wrote:
> 
> 
> 
>   Paolo,
>   
>   You may want to check if the FTP cable has a 100 Ohms characteristic
>   impedance which would make it compatible with interfaces designed
> for UTP
>   cable. STP cable is supposed to have a 150 Ohms impedance which is
> not
>   compatible with standard 10baseT interfaces which are usually
> designed for
>   UTP.
>   
>   Eric
>   
>   ===
>   
>   Éric Meunier
>   Hardware Architect
>   
>   E-mail: eric.meun...@ca.kontron.com < > 
>   
>   Kontron Communication Inc. (Teknor)
>   616, rue Curé-Boivin
>   Boisbriand, Québec
>   Canada, J7G 2A7
>   
>   Tel: 1-450-437-4661 ext. 2419
>   Fax: 1-450-437-8053
>   
>   Web:  < > 
>   
>   
>   
>   -Original Message-
>   From:   Paolo Roncone [SMTP:pronc...@cisco.com]
>   Sent:   Thursday, September 06, 2001 4:18 AM
>   To: Doug McKean
>   Cc: EMC-PSTC Discussion Group
>   Subject:Re: STP vs FTP Ethernet cables (2)
>   
>   Doug,
>   
>   I re-paste the first part of the definition in IEEE 802.3
> (2000):
>   
>   <<1.4.249 shielded twisted-pair (STP)cable: An electrically
>   conducting cable,comprising one or more ele-
>   ments,each of which is individually shielded.There may be an
> overall
>   shield,in which case the cable is
>   referred to as shielded twisted-pair cable with an overall
> shield
>   (from ISO/IEC 11801:1995)>>
>   
>   My understanding is that "elements" should refer to
> individual PAIRS
>   (signal/return), rather than single wires. But - as I said in my
> previous
>   e-mail - I'd like to check whether this is put into practice by some
>   vendors. So far I didn't get any clue on this.
>   The STP cables that I found so far (form a couple of
> vendors) have
>   just an OVERALL shield around all wires, and these are identical to
> FTP
>   (Foiled Twisted Pair) cables that are also on the market.
>   I agree with you, something doesn't sound right...
>   
>   Paolo
>   
>   
>   At 09:36 05/09/2001 -0700, Doug McKean wrote:
>   
>   
>   
>   Paolo Roncone wrote:
>   >
>   > The reason of my inquiry is that we bought