As Mr. Woodgate has been tirelessly pointing out, the limits are set to
minimize complaints, but also cost. And safety isn’t an issue. If a medical
device must wok anywhere under any circumstances, then it is like the
safety-critical features of an automobile and the limits must go WAY up.
Ken Javor
Phone: (256) 650-5261
________________________________
From: Cortland Richmond <k...@earthlink.net>
Reply-To: <k...@earthlink.net>
List-Post: emc-pstc@listserv.ieee.org
List-Post: emc-pstc@listserv.ieee.org
List-Post: emc-pstc@listserv.ieee.org
Date: Mon, 2 Nov 2009 08:40:31 -0500
To: <emc-p...@ieee.org>
Subject: RE: Where does 3V/m & 10V/m in RI come from?
How old is the 3V/m,10V/m requirement? It was, what, 25 years ago?, the FCC
and EPA here surveyed fields in Spokane, Washington, and concluded that levels
in the AM broadcast band were not a threat to health (never mind arcs from
ungrounded metal structures) at ~600 V/m. But would a AED work there? I've
seen a paper regarding AED malfunction due to 16.67 Hz fields under overheard
railway power in continental Europe.
Is the standard immunity level really sufficient?
Cortland Richmond
KA5S
----- Original Message -----
From: Haynes, Tim (SELEX GALILEO, UK)
<mailto:tim.hay...@selexgalileo.com> <mailto:tim.hay...@selexgalileo.com>
To: emc-p...@ieee.org
Sent: 11/2/2009 4:52:33 AM
Subject: RE: Where does 3V/m & 10V/m in RI come from?
Dear All,
Where does 3V/m come from? I do not know but if I run some numbers∑
E(dBV/m)=P(dbW)+14.77+G+20log(1/Distance)
How close would you put a 10kW transmitter to housing? 300m? what
antenna gain? 6dB?
E=40+14.77+6+20log(1/300)
E=60.77-49.5 = 11.27 dBV/m
=3.66V/m
Try some other realistic examples then take a „view‰ on what number you
would set as an immunity limit.
There will be some occasions where 3V/m is too low but do you make all
equipment meet higher levels or do you set levels that satisfies most
situations most of the time? Remember, most of the equipment that these limits
apply to are semi permanent as far as their location is concerned.
Somebody in the thread mentioned cars. Now cars are different.
EMC tests (as per standards) can NEVER be used for safety certification
as the tests do not simulate the „real world‰, either in maximum potential
exposure levels, not in terms of the multiple exposures that can occur. If you
want more on this, take a look at Keith Armstrong‚s presentation at
http://www.theiet.org/events/2009/digests/emcuk/armstrong-vehicles.cfm?type=pdf
Regards
Tim
************************
Tim Haynes A1N10
Electromagnetic Engineering Specialist
SELEX Sensors and Airborne Systems
300 Capability Green
Luton LU1 3PG
( Tel : +44 (0)1582 886239
7 Fax : +44 (0)1582 795863
) Mob : +44 (0)7703 559 310
* E-mail : tim.hay...@selexgalileo.com
P Please consider the environment before printing this email.
There are 10 types of people in the world-those who understand binary
and those who don't. J. Paxman
________________________________
SELEX Sensors and Airborne Systems Limited
Registered Office: Sigma House, Christopher Martin Road, Basildon,
Essex SS14 3EL
A company registered in England & Wales. Company no. 02426132
********************************************************************
This email and any attachments are confidential to the intended
recipient and may also be privileged. If you are not the intended
recipient please delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or
distribute its contents to any other person.
********************************************************************
-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list. To post a message to the list, send your e-mail to
<emc-p...@ieee.org>
All emc-pstc postings are archived and searchable on the web at
http://www.ieeecommunities.org/emc-pstc
Graphics (in well-used formats), large files, etc. can be posted to
that URL.
Website: http://www.ieee-pses.org/
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas <emcp...@socal.rr.com>
Mike Cantwell <mcantw...@ieee.org>
For policy questions, send mail to:
Jim Bacher <j.bac...@ieee.org>
David Heald <dhe...@gmail.com>
-
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
<emc-p...@ieee.org>
All emc-pstc postings are archived and searchable on the web at
http://www.ieeecommunities.org/emc-pstc
Graphics (in well-used formats), large files, etc. can be posted to that URL.
Website: http://www.ieee-pses.org/
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas <emcp...@socal.rr.com>
Mike Cantwell <mcantw...@ieee.org>
For policy questions, send mail to:
Jim Bacher <j.bac...@ieee.org>
David Heald <dhe...@gmail.com>
-
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
<emc-p...@ieee.org>
All emc-pstc postings are archived and searchable on the web at
http://www.ieeecommunities.org/emc-pstc
Graphics (in well-used formats), large files, etc. can be posted to that URL.
Website: http://www.ieee-pses.org/
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas <emcp...@socal.rr.com>
Mike Cantwell <mcantw...@ieee.org>
For policy questions, send mail to:
Jim Bacher <j.bac...@ieee.org>
David Heald <dhe...@gmail.com>
