Tania Grant wrote:
Amund,
My minimum criteria and recommendation has always been at least 6dB.
However, how many engineering managers, upon finding a 1.5 dB margin
in
their favor, rule ship it!
nod
Although in some markets, there are customers who
require -6dB under the Class A limit.
robertj wrote:
Ever since I saw this, I have been wondering what's going on in the
mind of this guy:
- doesn't have a clue
- can probably get away with this
- my tools are in good shape, everything's OK
Well, he is working next to a wet bar.
Doug McKean
Lazy... yes maybe or they might have trouble with coordination of the
different processes as development, pre-tests, development, final tests, all
files completed, ship it to the marked, etc
But I assume that they will not put it into the marked, because they are not
allowed. So they might
The surge test in 61000-4-5 is for testing for the effects of a lightning
remnants getting into the mains or an I-O/Telecom line. Some product
committees require surge tests to any power port, regardless of the source
of that power, but it seems to me that unless the 24V power is from a
How much of a temperature increase are we talking about,
how much do emissions increase, and what frequency(s)
increase in emissions?
- Doug McKean
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion
I read in !emc-pstc that Jennifer Banh jb...@bb-elec.com wrote (in
ndbblhfjolohjickdldooeofclaa.jb...@bb-elec.com) about 'surges on
24VAC', on Mon, 17 Dec 2001:
I am currently trying to test a product of ours that falls under 50082-1
generic standard for light industrial equipment.
If this is
Special temporary authorization or experimental license sounds good to
me, but in this case it is only a regular radio equipment which has been
re-designed and installed in a well known radio system.
But I agree and ask the same question as you do Don, is there a route for
special temporary
As far as I know the product shall be produced in a large scale. The reason
for putting it on the marked for a time limiting period is (again as far as
I know) to run the product ( beta version) in a test installation and
thereafter will it go through the entire test program (EMC, LVD, etc). It
Tania and Amund,
IMHO, the margin of compliance should be at least equal to or greater than
the measurement uncertainty. Measurement uncertainty for radiated
emissions is generally in the range of 3 to 4 dB for most labs.
Jim Hulbert
Pitney Bowes
Is there a route for special temporary authorization or experimental
license for a specific customer location? This may be on a spectrum
authority (SA) by SA basis. Just do it! may be a fine logo for selling
shoes, but does not work in legal arenas.
Don Umbdenstock
Sensormatic Electronics
Tyco
As you are well aware, the physics behind acoustics and electromagnetics are
very similar. The term overtone definitely has an acoustic pedigree,
whereas the term harmonic has been adopted by electrical engineering. But
the 1st overtone explicitly contains the info that we are talking about a
Ghery -
He is correct. There are DELTA configured transformers with
one phase earthed in the US. This is referred to as corner
grounded.
Refer to
http://saskpower.apogee.net/foe/ftdttd.asp
for a brief on the applications. The site is incomplete
(overall), but has some useful information.
John Shinn wrote:
If we refer back to the series, and refer to the n-th term, we
would all be on the same page (and harmonic).
And in harmony!
Cortland
(disclaimer: my views, not Alcatel's!)
---
This message is from the IEEE EMC Society Product
Hmmm . . .
Sounds to me that due to the limited marketing of the
product, the manufacturer doesn't want to absorb
the expense of compliance testing.
Generally speaking, while a compliant test report
(especially from a good independent lab)holds
weight, as has been noted on several occassions
This whole issue boils down to semantics and how we count and use numbers.
The first issue is what is a harmonic. A harmonic is a multiple of the
fundamental.
This can be seen when we look at the Fourier series:
V(t) = a(0) + a(1)sin(wt) + a(2)sin(wt) + a(3)sin(wt) + ...
where a(n) is the
Ken:
I think that you did not miss too much - my Physics 101 however was over 50
years ago and harmonics were only
mentioned in acoustics! Now, who wins?
Greetings,
Bogdan.
Ken Javor wrote:
I haven't been following this train but my recollection of definitions from
Physics 101 more than a
Hello everyone,
I am currently trying to test a product of ours that falls under 50082-1
generic standard for light industrial equipment. Our problem is that we
have a 24VAC power input port. The generic standard calls out for EN
61000-4-5 on AC power input ports. After looking at EN
Gentlemen:
I certainly did not intend to start philosophical contortions!
Season's greetings and a harmonic(*) New Year!
Bogdan.
(*) Now what will this start
lfresea...@aol.com wrote:
Mike,
I don't go with you on this one...
0 implies nothing ( prehaps 0 ac ) ... therefore the 0th
Have a look at the manufacturer's data sheets for the capacitors, and you'll
see spec's or graphs indicating the % capacitance change vs. temperature.
This can be substantial for ceramic cap's in particular. I don't know how
much of an effect it is for the typical film-type X and Y cap's, but
I can't speculate on the reason for the increase in leakage current;
however, I suspect you have a thermal design problem with the switching
circuit. I have seen an increase in conducted emissions due to a change of
the switching waveform - e.g. rise and fall times and ringing - once the
product
I read in !emc-pstc that POWELL, DOUG doug.pow...@aei.com wrote (in
b44016f6854cd511a6470003476b45e4381...@exchange.aei.com) about 'What
happened to the IEC60417 symbol library?', on Mon, 17 Dec 2001:
My questions was not
about IEC60617 the Graphical symbol library for use on diagrams (drawings
I read in !emc-pstc that lfresea...@aol.com wrote (in 169.5d0f58e.294f6
e...@aol.com) about '2 Phases in North America', on Mon, 17 Dec 2001:
0 implies nothing ( prehaps 0 ac ) ... therefore the 0th harmonic is
dc???
That fits with Fourier analysis.
if a squarewave is made up of odd
Amund,
My minimum criteria and recommendation has always been at least 6dB.
However, how many engineering managers, upon finding a 1.5 dB margin in
their favor, rule ship it!
Education (repeated brainwashing of as many 'powerful company managers) has
been my response;-- but that often takes
Is the manufacturer serious, or completely ignorant?
If serious, I would disassociate from them as much as possible. If merely
ignorant, and you have some sort of association with them, I would recommend
that you educate them fully.
Another thought, -- is this product slated for mass
I read in !emc-pstc that oover...@lexmark.com wrote (in 200112171644.LA
a08...@interlock2.lexmark.com) about 'Sometimes product safety just
isn't enough', on Mon, 17 Dec 2001:
There are, however, some winged creatures that walk on all fours that you may
eat: those that have jointed legs for
Ever since I saw this, I have been wondering what's going on in the mind
of this guy:
- doesn't have a clue
- can probably get away with this
- my tools are in good shape, everything's OK
Bob Johnson
ITE Safety
-Original Message-
From:
There are many such local services in the US. The only services you can
dependably expect are the
120/240 (center tapped) residential service
120Y208 three phase business/commercial service
277Y480 three phase light industrial service
There are many other conventions based on peculiar industries,
I can see that this subject hasn't fazed ANYONE.
Cortland
(speaking, as usual, for myself - and not my
employer)
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit our web site at:
Hello all,
On this topic, there's a fair amount of confusion going on in this group.
Which surprises me, since for the most part, people who are involved with
regulatory issues are more careful in their reading. My questions was not
about IEC60617 the Graphical symbol library for use on
Electric utilities genreate and distribute 3 phase power. At the load,
then, some power conversion strategy is employed to derive 2 phase
power. For instance, by adding a secondary winging on a 3 phase
transformer on phases A and B with 47% of the winding on phase A and 53%
on phase B, the
In the spirit of the season:
John wore clothing made of camel's hair, with a leather belt around his waist,
and he ate locust and wild honey.
Matthew 3:4, Mark 1:6
There are, however, some winged creatures that walk on all fours that you may
eat: those that have jointed legs for hopping on
The main page for the site is still up, just none of the
content we all seek.
http://w3.hike.te.chiba-u.ac.jp/iec417/ver2.0/html/index.htm
l
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
---
Failed on the first try. Let's try again.
Peter
-Original Message-
From: Peter Tarver [mailto:peter.tar...@sanmina.com]
Sent: Friday, December 14, 2001 8:57 AM
To: 'EMC-PSTC Forum'
Cc: 'Barry Esmore'
Subject: RE: 2 Phases in North America
This is a recurring topic.
While
fortunately we are omnivores
and while preferring to dine on the upper branches
of the food chain tree
nothing prevents homo sapiens sapiens from thriving on the lower branches
even though they don't look or smell so pretty,
everything's OK so long as our internal pathogen and infection defenses
Group.
I am interested to find out peoples opinions on a particular trend we've
seen time and time again on most switch mode PSU's. It seems that once a PSU is
warm its earth leakage decreases and its EMC emission performance decreases
(i.e. it gets noisier). This would suggest that there is
I haven't been following this train but my recollection of definitions from
Physics 101 more than a quarter century ago is that the fundamental is the
first harmonic. The first overtone is the second harmonic. These are/were
accepted definitions.
--
From: Cortland Richmond
Mike,
I don't go with you on this one...
0 implies nothing ( prehaps 0 ac ) ... therefore the 0th harmonic is
dc???
if a squarewave is made up of odd harmonics, we would have to rethink that,
correct?
Derek.
---
This message is from the IEEE EMC
Group,
We are looking for an EMCO model 7140 which is a Fiber Optic to RS-232
converter for their Isotropic probes models 7120, 7121, etc. If any knows of
one please contact me directly, I have tried the usual routes of used
equipment and contacting EMC Test Systems directly, currently
-Original Message-
From: James Collum [mailto:james.col...@usa.alcatel.com]
Sent: Friday, December 14, 2001 1:29 PM
To: emc-p...@majordomo.ieee.org
Subject: Re: Sometimes product safety just isn't enough
Following a recent airline flight, I was given a bag of peanuts, marked
Peanuts
This could be interesting::; if 50/60 is the 0th, then 100/120 would be the
1st ?? Makes sense to me!! No harmonics of the fundamental frequency would
be the 0th; and 1st harmonic would be at twice the fundamental
frequency.
(I know this is not the convention, but it seems logical: first
I also learned, that there is a three-phase delta system in USA with 500 Vac
per phase.
One phase (L3) is earthed.
Is this system very often used in USA?
Is it correct information, that L3 is always earthed and not L1 or L2.
Horst Haug
-Ursprüngliche Nachricht-
Von:
This particular labeling of Nut products is not an isolated event.
Pick up viturally any container of mixed nuts and it will have a similar
warning.
Of course don't start reading too many food labels, it can get really scary.
FDA's Food Alergen page is:
I read in !emc-pstc that Andre, Pierre-Marie pierre-
marie.an...@intel.com wrote (in 9985493A802AD5118C4E0090274627535EC2EE
@swsmsx34.isw.intel.com) about 'Regulatory General Discussion : ouput
of Compliance group', on Mon, 17 Dec 2001:
The good argument is really in the FULL implication of the
Doug,
thanks you for your inputs.
The good argument is really in the FULL implication of the Compliance group
in the design process right ? with full power to sign off the design changes
best regards to all compliance engineers
Pierre-Marie Andre
Senior Approval Engineer
-Original
Bill - you absolutely correct in describing the North American system as
single-phase, 3 wire. After all, that is how it is described in Annex V,
Figure V.4 of IEC60950:1999 - and there is NO WAY that IEC TC74
could be wrong, is there ? (especially since the US committee must
have voted yes, to
If we're smart (are we?) we'll say fundamental, and let whoever wants to
argue what 2nd means have the arena all to themselves!
I would say there are harmonics of the second order, third order, and so
on, to which we refer, in short, as the second and third harmonics (and so
on). Don't forget,
Hi Group
I have a question regarding working voltage measurement of IEC 60950
we have a E.U.T.(switching power supply)
I want to clarify the measurement of working voltage
1. Using an oscilloscope having an adequate bandwith and using a high
impedance probe (100Mohm), and adequate integration
Cortland:
I always thought that 50 Hz or respectively 60 Hz was the 0-th harmonic! Was
I mistaken? (I would not be surprised!) (: -) !!
Bogdan.
Cortland Richmond wrote:
This is rather similar to asking what the first harmonic of the power line
frequency is. (grin!)
Cortland
Jayasinghe,
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