Doug,
One of the best resources I've seen on the topic is called PROTECTION
OF ELECTRONIC CIRCUITS from OVERVOLTAGES, by Ron Standler (published
by John Wiley and Sons, ISBN: 0-471-61121-2.
Dave Tarnowski
Senior Engnr.
Whirlpool Corp.
St.
I am hoping to purchase a 1 to 5 Ghz amplifier to be used in conjunction
with a spectrum analyzer to measure emissions at 3m to FCC requirements.
With a 1 MHz bandwidth into a HP microwave analyzer we can only currently
measure at 1m.
Can we get away with measurements at 1m?
Can anyone
Charles,
If you want to CE mark a component which has no intrinsic value (that
is, it must be operated via another component),is CE marking illegal?
Also, is a Declaration of Incorporation (DOI) needed instead of a
Declaration of Conformity (DOC)?
--- Grasso, Charles (Chaz)
Rich
The obvious question I would have is... why couldn't you test at a higher
current for longer time meeting both requirements? For example 30A for two
minutes. I know the document indicates a maximum current, but does this make
sense?
OK I guess I know understand what you mean by Technical
Hi Carmen:
You ask how to resolve the difference between two,
different production-line (routine) test standards.
If your product is certified by CSA, then you test
to the 30-ampere value.
If your product is certified by a CB Certificate
and Test Report, and the issuing body invokes
EN
Hello all,
I want to clarify some of my thoughts regarding the ground bond
specification for production line.
EN 50116 for ITE specifies the earthing terminal or earthing contact may
not exceed 0.1 ohms when 1.5 times the current capacity of hazardous
circuits is applied, but not more
Hello all,
I want to clarify some of my thoughts regarding the ground bond
specification for production line.
EN 50116 for ITE specifies the earthing terminal or earthing contact may not
exceed 0.1 ohms when 1.5 times the current capacity of hazardous circuits is
applied, but not more than 25
Mike, I do not know if it is in the FCC rules or not, but your cell phone
service provider may not take lightly such actions. Cell phones make use of
line of site and low power to be a cell. Once you are up in the air, your phone
can easily try to connect to every cell site in the state (and
Hi Kamran,
I've run into this problem myself. Usually, it is because the test
conditions you use are different from what the vendor is using. They may be
loading the EUT to full capacity and/or using a thermocouple attachment
method different from yours. In the case where your product's
Posted for John:
:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
Ed Price
ed.pr...@cubic.com
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
619-505-2780 (Voice)
619-505-1502 (Fax)
Military Avionics EMC Services Is Our Specialty
Question from an ex collegue that's probably best fielded to the group.
Which safety standard (European) would be applicable to a small (1 metre by 0.5
metre, height ??) machine used for end of production line testing of SDRAM's?
The unit is non portable single phase (60 Amps max).
Sorry but
The recent August 1999 issue of Conformity magazine indicates that indeed
the test methodology of C63.4 does include the open chassis test and the 6
dB above limits. The article indicates a clarification was made about this
process in a recent OET notice. The notice itself wasn't identified so
Subject: Transient Surge Suppression
Mighty Experts of EMC,
I have a question concerning the determination of the right Transient
Suppressor to use for controlling Lightning Surges.
How do I determine the correct size and type of surge suppresser to use
(MOV's, Spark Gaps, etc...) to help my
Dear Kamran,
Obtaining a temperature test results that is 10-15 degrees higher or lower
than your vendor is not unusual at all. We experience this all the time
with major test houses. I have had many cases where an experience test
engineer in a test house measures as much as 20 degrees lower or
Kamran,
As John Crabb pointed out, making measurements at different points will give
you some variation due to hot spots etc. What most people miss is that
thermocouple readings are affected by magnetic fields. To get a correct
reading, turn power off and take a reading immidiately after the
Hello Kamran,
I have been faced with this problem many times in the (nearly 35) years
that I have been involved with such measurements. In my experience, this
is the major and problematic correlation factor (in the product safety
domain). It is the one that stands out above all others, when
To all my distinguished colleagues.
I wish to thank you for your responses to my call for help, and inform you
of the finial outcome.
Some of you I have contacted directly and some I have not (due to time
constraints) but I want to thank all that have responded very much. I have
read and
Kamran,
The method used by most of the better magnetics houses is to embed
thermocouples into the transformer during construction of a sample. The
resulting temperatures will be higher than external measurements.
Scott Lacey
-Original Message-
From: Kamran Mohajer
Kamran,
When UL or Intertek does safety testing (UL 1950, IEC 60950) on one of our
units that has coils or transformers in it they apply the thermocouples to
the top (highest) horizontal surface of the coil or transformer for their
temperature rise (heating) tests. I can usually find the
Dear Michael,
For European requirements, you have to read the EN55022 and its Amendments 1
and 2. In the Amendment1, the chapter 9.1 explain what you have to do with your
mother board. You have to test it in a commercial unit (classB) and if the test
results are OK, then you can affix the CE
Michael,
In looking at the standard to answer your question, you should refer to
Section 8.1 of the most current EN55022 (EN55022:1998/CISPR 22:1997), which
was published in the OJ earlier this year and was mandatory as of January of
this year.
Specifically, the 10th paragraph of section 8.1
As far as I know, the EU has not adopted the insane FCC Class B compliance
process. So there is NO procedure for marking a motherboard as a compliant
unit.
What you can do is test it in a system (just like the old days) and mark the
motherboard based on that test ALONE.
If I understand your
Concrete is a lousy insulator. It is frequently used as a poor conductor
in grounding systems. I think the conductivity of concrete was first
described by Uffer (spelling ???) after his work on protective grounding of
munitions bunkers. I can't find my copy of his paper right now so I can't
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