Dear subscribers,
I have read a news regarding on 3 Sept 02, UK Department of Trade Industry
(DTI) applied EMC Generic standard EN50081-1 Radiated Emission to test for
compliance on a AC Hair dryer, which claimed to interfere TV reception. The
hair dryer failed the test and the importer was
Hi Brian:
The environment being considered is a switching power supply. The technique
that safety agencies use to simulate a SFC on a power FET does not seem,
IMHO, to simulate the actual failure mode of the device. To wit: when the
mosfet fails short, it blows itself open; so
Dave Cuthbert write
the point at which ferrites are placed will not always have a common
mode impedance of 50 ohms. Here's An example: a large DUT has a 1 meter
long cable that connects
Not always; make that rarely.
Comments about the 150 ohm impedance are on target. That might be
David et al,
I've checked further and found the teldir site has changed to the following:
http://www.infobel.com/teldir/default.asp
Maybe that's why their servers were always busy. Who knows.
Anyway, IHTH you more.
Best regards,
Ron Pickard
rpick...@hypercom.com
Hi John:
The only other problem that I know of is distribution
transformer overheating. But, I believe such
transformers are very much larger than 3 kVA, so 3 kVA
of non-linear loads would have very little effect.
I mean *concentrations* of loads, individually below 3
What are the unique testing requirements for a power-line based LAN (i.e. the
information is transported on the powerlines within a home as an example) for
CE
mark? Would the power line harmonics be an issue? ANy unique set-up besides a
couple
of devices exchanging info?
Hans Mellberg
Brian,
I believe that forcing a FET failure would be a good test but should be in
addition to the mechanical short method. If your power supply is safe for both
failure modes that would be great. The fuse should open before the failed FET
can cause a heat or fire problem. And it was already a
Chris' Maxwell equations look correct. But the point at which ferrites are
placed will not always have a common mode impedance of 50 ohms. Here's An
example: a large DUT has a 1 meter long cable that connects to the ground
plane. At 75 MHz the common mode impedance of the cable, at the DUT, is
Yes sir, this is another thing I've wondered about; i.e., simulating the big
bus cap (short) SFC by applying a mechanical short accross the terminals. Does
not really demonstrate what would occur if the cap itself fails. A blown
electrolytic can be very messy.
I am beginning to wonder about some
The EM radiation from wires with and without ferrite cores can be simulated
with NEC. The required parameters are: length of wire, physical orientation,
how the end is terminated (floating? To ground?, frequency, the RL model of
the ferrite). Then one can move the ferrite around to see what
Wow, I would have to think a while about this. The first thing that comes to
my mind, is the risk any greater than the bulk cap failure that spew debris
around, and sometimes catch fire? There is no reasonable way to simulate that.
Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
I believe that selecting the right combination of ferrites once, by testing
them to provide at least 15 dB S21 should do it. Then it should be a matter of
keeping it documented and used in a test-procedure, to ensure that every time
one uses the same arrangement.
Regrading the proposal that
I haven't been following this thread closely, so if the following has
already been addressed, I apologize. I noticed this several years ago at
the office building I worked in at the time. My cube moved from one end of
the building to another, and my computer wouldn't always start - it took
I read in !emc-pstc that Chris Maxwell chris.maxw...@nettest.com wrote
(in 83d652574e7af740873674f9fc12dbaaf7e...@utexh1w2.gnnettest.com)
about 'EN55022:1998 + A1:2000' on Wed, 29 Jan 2003:
If the standard is assuming a 50 Ohm system, doesn't this breakdown to a
simple
calculation?
Quite
I read in !emc-pstc that Scott Douglas dougl...@naradnetworks.com
wrote (in 5.0.2.1.2.20030129141347.00a63...@pop.business.earthlink.net
) about 'Declaration of Conformity' on Wed, 29 Jan 2003:
Please forgive my mental lapse here. I know this subject has come
up before. This is a
I read in !emc-pstc that Gary McInturff Gary.McInturff@worldwidepackets
.com wrote (in 4e9a9436c008314eaa32033b23e96fd90b0...@thorondor.wwp.co
m) about 'RTTE directive.' on Wed, 29 Jan 2003:
Anybody have a link to peruse and purchase this, and a brief synopsis.
Replied to a previous e-mail
Good People of PSTC
The environment being considered is a switching power supply. The technique
that safety agencies use to simulate a SFC on a power FET does not seem, IMHO,
to simulate the actual failure mode of the device. To wit: when the mosfet
fails short, it blows itself open; so the
I read in !emc-pstc that Gert Gremmen g.grem...@cetest.nl wrote (in
mpeeiccjhhndekobpnnbmeegckaa.g.grem...@cetest.nl) about 'EN55022:1998
+ A1:2000' on Wed, 29 Jan 2003:
Proposals are on their way to specify
both transfer attenuation (first) and
input CM impedance of those clamps (later)
The
The scope of these standards includes all equipment having an input current
upto and including 16A per phase and intended to be connected to a public
low-voltage distribution systems of between 220V and 250V at 50Hz line to
neutral. Does public infer that only consumer goods that use residential
Ghery Pettit wrote:
Chris,
You can indeed make your own, but my bet is that A2LA or NIST NVLAP
inspectors will want to see calibration data, not calculations.
Now, if we just had a published calibration technique...
This is still not rocket science. Using Z = 138*(log OD/ID) --- for an
air
Indeed, a very good point!
I wonder what is meant by the 50 Ohm system does that mean a function
generator with 50 Ohm output impedance, 50 Ohm cable and a 50 Ohm load? (This
could be simulated nicely by connecting a function generator to a 50 Ohm
spectrum analyzer input using 50 Ohm cable)
I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in
200301291623.iaa07...@epgc264.sdd.hp.com) about 'Unity Power Factor'
on Wed, 29 Jan 2003:
Hi John:
In the USA, this has largely been fixed by a change in
the USA National Electrical Code.
There must be quite a
David,
As for getting an actual Iranian telephone book, I'm afraid I cannot help you.
However, you might
want to try the following link. If you're not familiar with it, it provides
telephone number/address
search capabilities for essentially any country on the planet by linking to
localized
For anyone looking for a very useful piece of Product Safety test gear, you
can’t beat Associated Research’s line of automated Compliance Analyzers.
I have an extra one and am offering it for sale on eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem
You're right that the link I gave only gets you a copy of the Directive
without the figures. The only downloadable versions I've found that do have
the figures are the .tif format ones available if you search on the document
from the following location:
Hello All:
Would any one have a contact(s) with some any one that has an up to date
Iranian Telephone book?
We are seeking information (translated into English) which is generally
contained in the first few pages of the telephone book, which identifies
specific numbers for calling different
Hi Ya'll,
Please forgive my mental lapse here. I know this subject has come up before.
This is a question of what to do with the Declaration of Conformity for the EU.
So please tell me what you do.
Do you put a CE mark on the outside of the box? Is this in lieu of the D of C?
Do you put the D
Chris,
You can indeed make your own, but my bet is that A2LA or NIST NVLAP
inspectors will want to see calibration data, not calculations.
Now, if we just had a published calibration technique...
Ghery
From: Chris Maxwell [mailto:chris.maxw...@nettest.com]
Sent: Wednesday, January 29, 2003
Ghery,
If the standard is assuming a 50 Ohm system, doesn't this breakdown to a
simple calculation?
Insertion Loss = IL = 20 x log((50 + Zf) / 50)where Zf is the ferrite
impedance
This could easily be solved for Zf if you assume IL to be 15dB (in this case
the dB are truely dimensionless;
Hope the following links help - I think it is what you are looking for :
Link to the text of the RTTE Directive :
http://europa.eu.int/comm/enterprise/rtte/dir99-5.htm
List of harmonised standards published in the Official Journal of the EC for
the RTTE:
Gert et al
Can anyone provide a spec for the ferrite. For example, what is typically
used in a CISPR 16 radiated power clamp? I am guessing when I say that I
believe these were originally a Philips type ferrite ring. I have two of
these clamps (Luthi MDS21 and Anritsu) and have found them to
Hi Group,
Proposals are on their way to specify
both transfer attenuation (first) and
input CM impedance of those clamps (later)
The radiation properties of the exposed wire will
vary widely depending on the CM load impedance.
The attenuation characteristic is to isolate
auxilary wire (and
Amendment 1 to CISPR 22:1997 (Amendment A1:2000 to EN 55022:1998) requires
that the clamps provide at least 15 dB of loss in a 50 ohm system over the
frequency range of 30 MHz to 1000 MHz. The use of extension cords is
prohibited. Can you guarantee that your bucket of doughnuts will meet this
From: Gregg Kervill
Sent: Tuesday, January 28, 2003 3:21 PM
Like most regulatory issues the answer is YES and NO.
Therefore it is dangerous and extremely misleading (to
many
lurkers) to apply a general answer to all conditions:
Generally the equipment is expected to protect itself with
Hi John:
In the USA, this has largely been fixed by a change in
the USA National Electrical Code.
There must be quite a number of installations that are not yet upgraded.
Where a problem existed, it was fixed by pulling
another neutral.
Are there any other problems
Anybody have a link to peruse and purchase this, and a brief synopsis.
I assume it calls out the standard EMC tests - EN55022, EN55024, and
Safety
standards, along with a standard or section which deals with the intentional
radiator portion of box, and harmonized frequencies
Subject: RE: MRA US-EU: Sectoral Annex Safety suspended
Dear Group,
Having read the document given, can anybody explain what it means?
You simple take the original terms and conditions and press the Delete key
For the benefit of those that did not archive the original documents I will
post
Hi Susan,
I would check with Met Labs who bought the old TUV Santa Clara facility.
Sorry, I don't have contact information for them.
Best regards,
Garry Hojan
Strategic Compliance Services (SCS)
www.regulatory-compliance.com
Now that DO-160D, change 3 is published, does anyone have
Thank you Richard – this situation vividly illustrates the danger of
nuisances tripping – what message does that give to the Home Owner –
“FIT A BIGGER FUSE!”
That is why (some) CSA standards require a Turn-On Test – ON-OFF 10 times
within a minute – protection devices MUST NOT OPERATE.
I
Peter -
I agree that this is an acceptable result in the US and
Canada. There are, however, additional considerations:
For Pluggable Equipment Type A (to borrow a term from the
60950 standards), the largest branch circuit protection is
assumed during testing (20A) and there is no further
I am going to jump into this frey, here is my 2 cents...
In the case of Medical Electronics, if the fault condition would cause
more exposure of radiation to the patient than what was dialed in
(X-Ray, MRI, Ultrasound) that would be a BAD thing. End of subject.
dave garnier
From: Lou Aiken
Hello All:
I am trying to cost reduce an older, worldwide PSTN line interface design.
This circuit contains a pulse dialing transient limiter that was needed to
meet the pulse dialing requirements in the Netherlands and Australia. I
would like to take this circuit out and restrict dialing
Two points:
To assure the safety of your product consider not whether it is safe if the
breaker trips, but what is the failure mode of your product if the breaker
(which you do not provide) does not trip. If you rely on the breaker, you
need to properly specify it.
In the US, there have been
Hi Group,
Does anyone have a clear idea or knows a link that shows the differences
between the old and new 61010 standard.
Thank You
Charlie Martin
GE Panametrics
From: iun...@servomex.com [mailto:iun...@servomex.com]
Sent: Tuesday, January 28, 2003 9:33 AM
To: emc-p...@majordomo.ieee.org
Jim
I your case the required BASIC INSULATION is not present or adequate. BASIC
INSULATION provides a level of protection. The branch circuit provides an
additional level of protection if there is a failure of the BASIC INSULATION.
The standard in this instance allows the designer to provide an
Peter,
I do not have specifics, so I can only offer general information.
The use of external breakers is acceptable for testing and certifying products
that are hardwired to the electrical distribution of a facility for when fault
current or withstand testing is required. In the US, the UL
Ian,
In short.
There is an MRA between US and Europe that covers the Sectoral Annex EMC and
Telecom.
E.g for EMC, Conformity Assessment Bodies (CAB's) were assigned in the
Europe for FCC regulation as wel as CAB's were assigned in US for EMC
directive in Europe. An easy way for European
Rich and group,
Just one interesting point continuing the thought of fuse sizes for
branch circuit protection. Awhile back, I was conducting a series of UL tests
on a household food mixer. For one of the abnormal tests, UL required me to
use a 30 A time-delay branch circuit fuse (lamp
I read in !emc-pstc that Rich Nute ri...@sdd.hp.com wrote (in
200301281747.jaa29...@epgc264.sdd.hp.com) about 'Unity Power Factor'
on Tue, 28 Jan 2003:
Hi John:
No, this is not much of an issue for the U.S. (unless your facility
is
actually affecting the utility);
...
All
I can see that my manager would prefer to use Neven's approach - it is
probably much cheaper than buying clamps. However, does anybody have any
practical experience of this?
A reply from an accredited test house would be welcomed!
Thanks
Ian Gordon
From: neve...@attbi.com
Dear Group,
Having read the document given, can anybody explain what it means?
As an instrument manufacturer selling products into both the US and EU do
I need to panic over this, or can I ignore it and sleep peacefully in my
bed at nights?
Regards
Ian D Unwin
Servomex Group Limited
Instead of paying big bucks for the clamps (I am not sure what the price is,
but I'm sure it is too much anyway :), why not buying a bucket of ferrite
doughnuts that can be used over cables. Or, when possible, building in-line
adapters out of sections of cables (maybe 1m long) and lining them
Here is what I think the requirements are:
If the product remains safe, within the meaning of the standard, and the
branch circuit overcurrent protection device does, or does not, operate as a
result of fault testing, internal overcurrent is unnecessary.
If the product does NOT remain safe,
Automotive products must comply with the Automotive Directive - this
actually requires additional elements beyond the
EMC Directive.
Safety issues are as one would expect - Fire and Energy Hazard - and are
potentially more serious than mains operated equipment because you do not
usually have
54 matches
Mail list logo
