Hi Dan.
Two ferrite manufacturers I use are Stewart and Fair-Rite. Both of
them have catalogs containing great detail graphs of performance of
their various materials.
Some of the 43 and 44 ferrite materials have very good low frequency
performance. I would suggest, because I have no
Gary, I was recently in conversation with UL about LEDs whereas I am
now being told that UL has convinced the European counterparts that
LEDs are no longer considered Class I Lasers and the requirements for
them to be tested as such has been dropped. UL no longer treats them
that way in
David,
Telecom (Bellcore) usage is to keep signal, surge and power currents off
chassis and safety grounds. This is understandable. It is due not only to
audio sensitivity, but to the need to protect equipment from substantial
peak (hundred of amps) surges at fairly high (thousands of volts)
A good way to think about this, especially on a larger size board, is to imagine
a transmission line resonator. Assume for the moment that the shielding
enclosure and the board ground are tied together at one point. In this case, the
board will go resonant when the length of the board ground
Thanks everyone. We do indeed want to use the LVD anyway, and have adopted
the interpretation for years that has now been made official by the
guideline quoted below.
Jim Eichner, P.Eng.
Regulatory Compliance Manager
Xantrex Technology Inc.
e-mail: jim.eich...@xantrex.com
web:
All,
I'm trying to convince a few people here that completely separating the
digital and chassis grounding on our product is not always the best way to
go. Unfortunately, a lot of the people I'm dealing with are ex Bellcore
engineers who worked a lot with isolated grounds and are convinced
I have always been reluctant to place ferrite beads in the ground path, but
I see them frequently in reference designs for USB and Analog Audio.
What kind material should this be and what characteristics would this type
of ferrite have. I am assuming this ferrite would not have 600 Ohm
Greetings all,
I have become involved in a discussion regarding potential ground voltage
differences between opposite ends of long network lines in industrial
locations. As I understand it these differences are the reason for some
network types floating cable shields or connecting them through
-Original Message-
From: Ted Rook [mailto:t...@crestaudio.com]
Sent: Friday, October 11, 2002 7:04 AM
To:
Subject: 160 Amp Triax
maybe you could try the DOD, they probably have something like
this to feed the deep space antenna at Arecibo ;-)
seriously now, I'm very curious to
Jim,
Please check out www.nebs-faq.com for some basic information about NEBS. I
created this site to answer some of the more common questions about NEBS.
You can also check out an article I wrote for Evaluation Engineering What
Every Startup Needs to Know About NEBS at
Creepage distance has nothing to do with current within the context of the
product safety standards.
Creepage distance is the distance across the surface of an insulating
material. The specific Creepage distance for any product safety application
is based on:
1) Working Voltage,
2)
David -
These are not harmonized standards. UL 891 bases it's
spacings on US electrical distribution standards, while
EN60439-1 most likely relies on IEC60664.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com
Greeting to all,
Our company makes Laboratory Instrumentation which many employs a small furnace.
In case the furnace control circuit fails, we have a secondary Over Temperature
Protection Circuit (OTPC) which opens a double pole relay to shut power off to
the heater coils.
In a new design we
Doug,
When I was developing network adapters at my previous company, we would use
a long cable-- close to the maximum length specified-- between the
equipment we were electrostatic discharge (ESD) testing and our support
equipment. These long cables were wound on the reels that the cable came
Hello George,
EN 55024:1998, the title of Table 4 is Immunity, input a.c. power ports
(including equipment marketed with a separate a.c./d.c power converter).
The table includes surge and fast transients. Seems like this issue must
have come up before.
Hope this helps,
Don Umbdenstock
Tyco
Regardless of what the standard says, and I believe it does apply to
the equipment through the power supply, what are going to tell you customer
when all you hard work in designing the product goes out the window after the
supply allows the system to be brought down. Hey, it cost me
maybe you could try the DOD, they probably have something like this to feed the
deep space antenna at Arecibo ;-)
seriously now, I'm very curious to know the application, or have we been
missiled by a typo?
Best Regards
Ted Rook, Console Engineering, ext 4659
Please note our new location
In addition to the new GR-63 that came out (and there are already
clarifications supplied by Telcordia, based on industry queries - call Rich
Kluge), Telcordia is now amending GR-1089 (November time frame) with some
drastic changes:
1. Ferrites are being banned from cables leaving the test
George, the product has to comply with the standards. In this particular
case, the product consists of two parts that operate together, and must
therefore be tested as a system. All of the power line tests apply when the
when the complete system is powered and operating.
Richard Woods
Ted,
thank you for your response. I do not claim to be an expert, but I cannot
accept that creepage has anything to to with the current flowing in a
circuit. Surely it is the voltage across the material and the CTI of that
material which determines the likelihood of tracking across the material
Actually,
I don't even know if you need to read a standard for this one...just think
about it for a second and apply some common sense.
So the power supply has passed EFT and Surge. That's great. What was the
criteria for susceptability? Many standards allow Criterion B performance
Hi Folks
Also take into consideration the requirements of the Product Liability
Directive which can effectively increase the 10 yr figure to a practical
number of around 13 yrs, and the US product liability legislation which can
be effectively unlimited in many cases.
Regards
John Allen
Something else to remember is that if the product has lines over 30m long
or (for some product standards) which pass outside buildings, then these
must also be surge tested. Burst testing on I/O leads is required if they
are over 3m long.
These tests may apply to the system as a whole.
Hi George,
I haven't got a copy of EN55024, but if it is anything like the format of
EN61000-6-2, then the info you are looking for will appear as 'notes' under
immunity testing of dc input and output ports will read ...
[EFTs Surge] Not applicable to input ports intended for connection
to a
Folks,
IEC 60825-1:2001 has an Annex G Information to be provided by manufacturers
of LEDs. This is an informative annex, the purpose for which is explained
in the above title.
I suggest that you start with asking your LED vendor to send you data in
conformity with the above. If you're lucky
Thank you everyone for your very informed replies on the subject.
'Endurance' and 'use' does indeed involve vibration. The units are used
on off-highway heavy duty vehicles and forklifts. The contacts are not
gold-plated and I am glad I didn't make that clear because the info
forthcoming (Thank
A usefull document for those looking for some insight in regulatory
approvals.
Regards,
Kris
-Original Message-
From: Antoniou, Christine [mailto:christine.anton...@aca.gov.au]
Sent: vrijdag 11 oktober 2002 9:02
Subject: Review of Telecommunications Customer Equipment Technical
Regulat
For EU, the requirement is specified in the various Directives. The
period is 10 years but it is not only the DoC that must be retained but
also the technical files.
From the LVD Annex IV section 2:
The manufacturer must establish the technical documentation .. must
keep it in the
Pardon my naivety, but how does '100 Mbit' relate to
frequencies of 30 and 60 kHz? Is this 100 Mbit per week?
(;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
http://www.jmwa.demon.co.uk
snip
First, a little background on auto negotiation. The IEEE
802.3u 100BaseTX auto
-Original Message-
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Thursday, October 10, 2002 12:23 PM
To: emc-p...@majordomo.ieee.org
Subject: Re: High Voltage Equipment/Appliance Wire
I read in !emc-pstc that POWELL, DOUG doug.pow...@aei.com wrote (in
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