John,
I'm certainly not as familiar with as many standards as you are, but
isn't the requirement, not so much that the PEC, must be on its own stud, but
rather than this connection must be the first, and then a double locking nut
to secure it? If there is remaining post length
Pat,
I deal with MOSFET and IGBT offline switchers running at some fairly high
power levels and switching frequencies. I've found that operating these
switchers in quadrature (or some other angle) helps considerably. In my
applications, the generation of RF emissions is in pulse edges of the
I'm with Jim.
The two-hole post feature is used for the Chassis Ground to Frame Ground
connection. The Batter_Return can be attached to the two-hole post feature
afterwards under some Central Office grounding architectures.
Marko Radojicic
Nokia Internet Communications
313 Fairchild Drive
Is anyone familiar with any requirement that limits the number of ground
terminations on a single stud?
Depends on type of equipment and country of application. But for example,
IEC 60204-1 EN 60204-1 (Electrical equipment of machines...)
14.1.1 The connection of two or more conductors to
Ken Javor wrote:
My way of thinking about this problem and others like it is to reduce it
to the simplest possible problem, and then look at the general case as a
linear extrapolation. In this case I look at the interaction of the direct
and single bounced ray during a site attenuation
Penny,
This is only partially correct. See the 5th bullet item in R9-11 of section
9.7.1 of Telcordia GR-1089-CORE issue 3.
Multiple bonding or grounding conductors shall not be secured by the same
bolt and shall not need to be removed to perform other service or installation
procedures. It
- Original Message -
From: Pat Lawler pat.law...@verizon.net
To: EMC-PSTC emc-p...@ieee.org
Sent: Wednesday, July 30, 2003 7:31 AM
Subject: Synchronizing DC-DC converters to reduce emissions?
We are designing a switching power supply for a customer that has
multiple outputs. Due
Nick wrote:
Is anyone familiar with any requirement that limits the number of ground
terminations on a single stud? I heard that the limit is two per stud but
I
was not able to confirm this with any of the standards we have.
Depends upon what you mean by ground?
I've had many products
Please provide the GR-1089 reference to ONE ground wire per stud inside
a chassis.
Thanks,
Bill Rea
Performance Technologies. Inc.
From: Robbins, Penny D. [mailto:probb...@telcordia.com]
Sent: Wednesday, July 30, 2003 9:56 AM
To: emc-p...@majordomo.ieee.org
Subject: RE: Number of Terminations
Look at cl 2.6.4 in 60950 and section F of the CSA Design Manual for 60950.
AFAIK, there is no limit for number of connections to a P.E. stud or screw;
for construction requirements, see above. There are limits for busbar-type
connections.
luck,
Brian
-Original Message-
From:
I think you might refer to IEC 60950 para 2.6.4.2 for the connection of the
PE. Table 3E will probably be used to govern how many you can have on a stud.
Scott
- Original Message -
From: Fred Townsend mailto:f...@dctolight.net
To: Momcilovic, Nick mailto:nick.momcilo...@qtiworld.com
If all the supplies have a switching frequency within a few kilohertz of
each other, and the resolution bandwidth of the measurement is 9 kHz, it
seems to me that the power bandwidth of the measurement doesn't depend on
the synchronization and that you'll obtain the same reading either way.
I
Pat Lawler wrote:
We are designing a switching power supply for a customer that has
multiple outputs. Due to the tight regulation requirements, all
outputs have their own PWM modulators and control loops.
The customer feels the RF emissions (as measured by CISPR 11) will be
reduced by
I read in !emc-pstc that Momcilovic, Nick nick.momcilo...@qtiworld.com
wrote (in 139803a793e0d311aff60050da2bc54005297...@qtiexch1.qgraph.com
) about 'Number of Terminations on a Ground Stud?' on Wed, 30 Jul 2003:
Is anyone familiar with any requirement that limits the number of ground
Telcordia's GR-1089 limits the number to ONE per stud.
From: Momcilovic, Nick [mailto:nick.momcilo...@qtiworld.com]
Sent: Wednesday, July 30, 2003 12:03 PM
To: emc-p...@majordomo.ieee.org
Subject: Number of Terminations on a Ground Stud?
Is anyone familiar with any requirement that limits
Dave,
I assume that in this utility vault , would be placed other electronic
devices, if that the case the unit have to meet the 50 mV/m.
Rachid Sehb EMC engineer
From: drcuthb...@micron.com [mailto:drcuthb...@micron.com]
Sent: Wednesday, July 30, 2003 11:44 AM
To:
Are we talking about electrical circuits or electronic? If we are talking
electrical there may be some concerns about current capacity that would limit
the number. If we are talking electronic circuits returning all ground
circuits
to a common ground point is a considered good design practice.
Is anyone familiar with any requirement that limits the number of ground
terminations on a single stud? I heard that the limit is two per stud but I
was not able to confirm this with any of the standards we have.
Thanks in advance for your help.
Sincerely,
Nick Momcilovic
Product Safety
Intuitively, I would think that any measures taken to de-synchronize the
switching of the power supplies would also improve conducted emissions.
-Original Message-
From: Pat Lawler [SMTP:pat.law...@verizon.net]
Sent: Wednesday, July 30, 2003 10:31 AM
To: EMC-PSTC
Subject:
CONFLICT of INTEREST NOTICE:
my employer manufactures SMPS.
In a properly laid-out SMPS, conducted emissions should not be affected in a
DC/DC converter that uses Class 1 construction; but converters that float the
input and/or output could see problems at both ends.
Stand-alone radiated
I am considering using a short range data link in an ISM band. It will comply
with FCC part 47, 15.249, which specifies a field strength of 50 mV/m at 3
meters. However, the device will be placed inside a utility vault, which has
about 30 dB of attenuation. Is there a way I can specify the field
These are protection standards. I can't attest to the links
providing the latest information, but this is a interesting
resource.
http://www.who.int/docstore/peh-emf/EMFStandards/who-0102/Wo
rldmap5.htm
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
I agree with you. Unsynchronized, the emissions will add randomly as the
square root of the sum of the squares. Synchronized, they add in phase,
coherently. The difference between these two techniques is
20 log (n) - 10 log (n) = 10 log (n) in dB,
where n is the number of PWMs, so the
From
http://www.fda.gov/cellphones/qa.html#36a
How does FCC Audit Cell Phone RF?
After FCC grants permission for a particular cellular
telephone to be marketed, FCC will occasionally conduct
“post-grant” testing to determine whether production
versions of the phone are being produced to
We are designing a switching power supply for a customer that has
multiple outputs. Due to the tight regulation requirements, all
outputs have their own PWM modulators and control loops.
The customer feels the RF emissions (as measured by CISPR 11) will be
reduced by synchronizing the
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