In defense of Intel (please wait a moment while I don my full body armor),
this is probably one of those things that only occurs on alternate rainy
Tuesdays when using certain specific brands of SDRAM.
Scott Lacey
-Original Message-
From: David Spencer
Mark,
If such a table exists, it was probably generated by one of the power
companies. If you can not obtain the information, your best bet would be to
measure several examples of each type of properly prepared joint. Measuring
new, clean, carefully torqued joints should give you a reasonable
Robert,
I have always found the European color codes (brown/light blue/green
w/yellow) to be best for dual market use. UL and CSA seem to have no problem
with the use of these. You will need to provide some kind of legend plate or
tag explaining the color codes, as many U.S. electricians are
: Thursday, March 30, 2000 7:05 PM
To: Lacey,Scott; Tony J. O'Hara
Cc: emc-p...@majordomo.ieee.org
Subject:RE: Mars Lander EMC problem?
Scott and Tony,
That means the sensor was unable to tell the leg jolt from the
landing shock
Mr. Wiederhold,
About a year and a half ago, I installed a whole-house fan for a relative.
The unit was clearly labeled inspect and lubricate annually. In addition,
there was a warning marked on the motor end bell about not attempting to
defeat the thermal cutout . Most locked rotor situations
Muriel,
As you are one who has studied Esperanto, I wonder if you would be kind
enough to list the Esperanto equivalents of the following words in English:
Freedom Liberty rightsprotesttyranny
justice property privacy
This is not simply curiosity,
Ray,
The answer depends on whether your compressor is a component or a finished
product. Component = yes, product = no way.
Scott Lacey
-Original Message-
From: Russell, Ray [SMTP:ray_russ...@gastmfg.com]
Sent: Friday, March 24, 2000 10:14 AM
To:
Martin,
While I may disagree with some of the technical content of various standards
(I think they need to add more details to accommodate smaller, more
distributed systems), I heartily agree with the need for them. The immunity
tests in particular represent real-world threats to equipment, and a
Exactly.
Scott Lacey
-Original Message-
From: Brumbaugh, David [SMTP:david.brumba...@pss.boeing.com]
Sent: Thursday, March 23, 2000 11:19 AM
To: emc-p...@majordomo.ieee.org
Subject:RE: Ambient Cancellation Device for OATS
To the group,
After monitoring the discussion for a while, I thought that I would share my
experiences. As a person who bears scars from encounters with sharp edges
inside equipment, I can state with certainty that outside CORNERS are by far
the worst offenders. Knocking off these corners at 45
Paolo,
Thank you for the information. I suspect that you are correct as to
the critical nature of the frequency modulation method. The design engineer
picked the device, probably as the cheapest vendor. The device did not
behave as I expected, based on some Internet research of
Robert, and the group,
Although I have only limited experience (1 instance) with dithered clocks, I
thought that I might share that experience with the group. I had a product
that was failing radiated emissions at one particular frequency with a
vertical antenna orientation. I tracked the problem
Giuseppe,
First, a question. What ill effects (to him or to household appliances) are
being caused by this EM noise?
Scott Lacey
-Original Message-
From: Rossi Giuseppe [SMTP:g.ro...@crf.it]
Sent: Friday, March 10, 2000 10:19 AM
To: 'emc-pstc'
Richard,
Readily accessible means not obstructed by furniture or equipment. The
shutoff will be wall mounted, in a visible location, at a height where
persons of short stature can reach it, but not so low as to require
crouching to reach it. Local codes may specify a height range. It should
also
Derek,
The points you make are extremely valid. Product testing should not be
merely a paper chase, with a certificate as the only goal. I agree that if
your product always gets bolted to a large metal structure, it should be
tested in a simulated condition. However, and I am guessing here, if
Forwarded for John Lindstrom:
-Original Message-
From: Linstrom, John (IndSys, GEFanuc, CDI)
[SMTP:john.linst...@cdynamics.com]
mailto:[SMTP:john.linst...@cdynamics.com]
Sent: Monday, March 06, 2000 12:48 PM
To: 'Lacey,Scott'
Subject:RE: Product Safety Certification
For those just looking for ergonomics information, there is an excellent
MIL-STD that covers nearly every aspect of human/equipment interface, with
reference dimensions for various percentages of a sample population. It
covers everything from desk height to strength required to turn knobs. I
lost
...@pb.com]
Sent: Thursday, March 02, 2000 8:52 AM
To: Lacey,Scott; emc-p...@ieee.org
Subject:RE: Surge Testing per EN 55024/EN61000-4-5
Scott,
The product I'm currently looking at uses a 2 -prong AC mains plug.
Actually
the supply
Chris,
In the case you mention, setting the CD player in its normal position on a
grounded steel plate should do. The unit may end up sitting on a steel shelf
unit along with other equipment with grounded chassis. I used such a setup
at home for years.
Scott Lacey
-Original
Ron,
Try to find a supplier to the marine electrical industry. Commercial fishing
boats require heavy-duty bonding. They usually use copper straps or large
braid. By the way, if the ground connection does not have to be flexible,
thin copper sheet works better than braid. The earth ground rod
Dave,
I have always seen this used for micro, as in dBuV = decibel microvolts.
It may also stand for decibel units. If so, a unit is most likely 1 volt
rms, a common unit in professional audio. The formula would be 20 X
LOG(input voltage/reference voltage), with LOG referring to LOG 10.
Scott
Joe,
It's been a few years, but Compliance Engineering used to sell Roberts
Antennas - Telescoping dipoles with coax baluns. The telescoping elements
were adjusted (by hand) using a tape measure. We used to mark a standard
inch tape measure with a permanent marker for convenience. They also sold
My, how public spirited of them.
Scott
-Original Message-
From: simon_...@emc.com [SMTP:simon_...@emc.com]
Sent: Tuesday, January 18, 2000 10:24 AM
To: emc-p...@ieee.org
Subject: RE: Lead Banned in Europe Japan?
A little research on the Internet showed that the proposal
John,
With a 12V battery system, you will have to address the issues of hazardous
energy - ie.the heating effects of battery current under short-circuit
conditions. Even a small battery pack can heat a wedding ring nearly white
hot.
Scott Lacey
-Original Message-
From:
Jim,
The situation you describe would be criterion C, because there is a
temporary loss of function and it is recoverable.
Scott Lacey
-Original Message-
From: Jim Hulbert [SMTP:hulbe...@pb.com]
Sent: Wednesday, January 12, 2000 3:08 PM
To: emc-p...@ieee.org
Subject: Surge
Fellow Listmembers,
I have a question regarding tiger tails used to improve transmission
characterisics of a hand-held transmitter (HHT). The HHT is basically a
dipole, with the chassis as the bottom element. The tiger tail is a
quarter-wave length of wire that connects to the shell of the
Max,
I think you have either a bad cable or poor internal connection in the VCR.
There should be no effect on signal when the VCR is off - the signal is
bypassed straight from the input connector to the output connector. Your
local Radio Shack sells an inexpensive adapter which couples two cables
James,
In our lab, I just spotted a tin-plated lug of the type you seek. It is
marked BURNDY SCRULUG, and is tin plate over copper, with a clamping plate
between the screw and the wire. I have no idea how old this lug is, or if
Burndy still makes them, but it might be a good idea to contact
James,
Most equipment today uses crimp-on ring terminals, secured to a ground stud
using a star washer and hex nut. The ground wire from the power inlet goes
on first, and other safety grounds are stacked on top, each with its own
star washer and nut. I have never had agency approval problems
Dick,
Try
http://law.etext.org
Scott Lacey
-Original Message-
From: Dick Grobner [SMTP:dick.grob...@medgraph.com]
Sent: Friday, December 17, 1999 1:09 PM
To: 'emc-p...@ieee.org'
Subject: CFR's
Does anyone out there know if you can download Code of Federal Regulations
Ned,
Any calibrated static charge meter should work ok. They run about $400 to
$600 dollars from many vendors (ACL, 3M, Ion Systems, etc.). You probably
will want to test worst case - dry pump, gloved hand, unit sitting on an
insulated
surface. One person pumps while the other holds the meter.
Derek,
We stock a 16 amp line filter which we have used on lower current products
specifically to prevent saturation of the choke when used as a protective
device for external events such as EFT. I put one on a product containing an
industrial computer supplied by a business partner to solve a
David,
Try National Semiconductor. I believe they manufacture most of the ICs used.
Scott Lacey
-Original Message-
From: david_l_tarnow...@email.whirlpool.com
[SMTP:david_l_tarnow...@email.whirlpool.com]
Sent: Tuesday, November 30, 1999 3:34 PM
To:
Egon (and fellow list members),
I think you meant to reply to Scott Douglas. Lately, I have received several
emails which were replies to him. Since most of them were probably initiated
by clicking on the Reply button, I suspect some internet glitch is at
fault. Scott's company is located about
Scott,
I beg to disagree, ... but, Halon, along with Freon and other compounds was
banned by the Montreal Protocol, ostensibly to protect the ozone layer.
Interestingly, the Freon replacements must, per the treaty, be phased out in
20 years - by coincidence about the time when the international
Muriel,
The usual method of measuring the impedance of a component is to insert a
non-inductive resistor in series with the component and measure V1 vs. V2,
where V1 is the voltage across the resistor and V2 is the voltage across the
component under test. At any frequency, the voltage ratio will
Scott,
CE compliant? I'm not even sure that my brain is Y2K compliant! :-)
Scott Lacey
-Original Message-
From: Scott Douglas [SMTP:s_doug...@ecrm.com]
Sent: Monday, November 15, 1999 11:18 AM
To: EMC-PSTC (E-mail)
Subject:Is Your
Barry,
Instead of drawing in Word, why not try the Paint program that comes with
Windows. The version that comes with Win95 and later actually has some nice
features, such as multi-size zoom, cut and paste with mirror, rotate, flip,
etc. If you hold down the SHIFT key while drawing with the
To the group,
Does anyone know of a source that will sell small amounts of semi-rigid coax
(hardline), preferably by mail?
I have a few small projects in mind.
Scott Lacey
-
This message is coming from the emc-pstc discussion list.
To cancel your subscription, send mail to
After reading Bill Lawrence's posting, I realized I made a typo error.
The last two numbers should have been 1 3/8 and 1 3/4.
The dimensions would then be:
7/80.875
1 1/8 1.125
1 3/8 1.375
1 ¾1.750
These are nominal values - the min and max values would be those which
Bill reported.
Jim,
I took a few quick measurements of workboxes, isolation transformers, etc.
in the lab, as well as the knockout openings in the cast housings of some of
our flow transmitters.
7/8 and 1 1/8 seem to be the most common for the smaller circuits, with 2
3/8 and 2 3/4 used for the heavier stuff.
Leslie,
The Fluke Model 51 or 52 should be adequate for your needs. These are
battery operated thermocouple instruments, single and dual input models.
They are relatively inexpensive, and I would strongly recommend the dual
input model for the extra features, as well as the ability to measure
To the group,
Can anyone recommend a paint or other (light colored) coating that can be
applied over ferrite tiles?
The lighting in the bat cave (shield room) is rather grim. It can be very
difficult to see when working inside of a cabinet. Photos of test setups
would also look better if there
Bill,
I think that the only time that you would have to discharge to the interior
metal is if the vents are large enough to admit the standard test finger.
This has a much more blunt shape than the contact point on an ESD gun.
Scott Lacey
-Original Message-
From:
Joe,
More data will be required before the group would be able to help with a
diagnosis. You say
that each instrument is on it's own line. Are you referring to an ac power
line? Also:
Is each instrument provided with it's own isolated ground receptacle?
Are they networked? If so, is the
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
Doug,
Concrete may be made to work as an insulator, but conditions will have to be
carefully controlled. Most concrete tends to be somewhat hygroscopic,
although this varies with mix variables including type of aggregate used. I
have heard that large concrete pads are successfully being used as
Carlos,
Over the years, I have designed and built a lot of this type of equipment.
It is actually easier to build in safety with this type of equipment rather
than a commercial product because component costs are not as much of a
factor. Here are a few rules to follow:
Identify and list all
Prop 65 sounds like another case of the technically illiterate creating
convoluted laws which burden the productive sector and create more work for
the bureaucrats. The entire electronics industry is tooled up for lead-tin
solders. I doubt that the California market is large enough to justify the
Ed,
I find your idea of a salt water ground plane very intriguing. I imagine the
salts used would involve more than just table salt, and the chemistry would
have to be checked and adjusted regularly, similar to a swimming pool. The
problem of stratification could easily be solved with circulator
OOPS!
In my recent posting, I proved that human memory is a very fallible thing. I
stated that in the failed GFCI outlet I examined, the sense coil measured
current in the GROUND conductor. Thankfully, Jim Eichner pointed out that
such a circuit would not fulfill the most important need for a
Leslie,
This is fairly simple using an RF signal generator and an oscilloscope
terminated at 50 ohms.
The RF generator must have an output impedance of 50 ohms. The trick is to
first measure the amplitude delivered at the oscilloscope from a known 50
ohm cable at 5 MHz or greater. Then, without
In my opinion, letting the cable insulation touch the probe body is never a
good idea. I always try to shim the cable and probe in order to center the
cable within the probe opening. The trick is to keep the shims outside of
the probe. A good trick is to make a V block out of wood, with a deeper
Kevin,
I heartily second Jeff's endorsement of the Thermotron SE Series. We have
several of the larger SE-1000-3-3 chambers in use. The integral 3.5 floppy
drive is a tremendous idea. Test setups are easily archived for future
reuse. The ability to capture a temperature log to disk for later
Daniel,
The key item which you should have is an anemometer probe. They are
available at reasonable prices. This will allow you to measure airflow at
the power supply under test. A simple box (length several times width and
height to linearize flow) with fans mounted at the outlet end will be all
Lou,
The best way to deal with an angry water moccasin, as any good-ol-boy can
tell you, is to dust them with a load of fine gauge shot. 100% effective,
with no ricochet danger to bystanders. There are even special snake loads
available in most revolver calibers. Fooling around with improvised
Doug,
Refractory Ceramic Fibers (RCF) look very much like white cotton fibers,
except that they are stiffer. They are used as insulation for heaters,
temperature chambers, etc. Look for them in your products around tanks,
heaters, and the like. They will usually be either wrapped in foil or
Lisa,
We use software from Chase for this. At each frequency step the generator
power starts off several dB below the level determined during calibration
(using field probes). Actual forward power is measured using a directional
coupler in the antenna feed. The modulation is turned on only after
While not quite as bad as the disaster Ed Price described, I once had to fix
a shielded room built to the specifications of a self-described RF
expert. This gentleman had convinced his management that he could build a
cheap and easy facility. The intended site was an unused loft on the fourth
Arjen,
For insulation over PCB traces, some types of dry film solder mask might be
suitable. These films are manufactured to a consistent thickness, and then
laminated to the PCB. You need to check with your board vendor as to types
and approval ratings. These films are very tough, just ask
[SMTP:chris_dup...@compuserve.com]
Sent: Wednesday, March 03, 1999 6:29 PM
To: Lacey,Scott
Cc: emc-pstc
Subject: RE: New EMC requirements proposed for IEC60335
Hi Scott.
You wrote:
It's sometimes all too easy to forget WHY we perform these tests. While
we are trying to comply
$0.02
I just thought I'd add my two cents worth. It's sometimes all too easy to
forget WHY we perform these tests. While we are trying to comply with
written requirements in order to pass, we are also trying to ensure
product
performance in the real world, which can be a very hostile place from
Craig,
-
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To the group,
I am hoping that someone has some good suggestions for inducing harmonic
distortion
to the ac line input of an instrument under test. The nominal input is
120Vac/60Hz.
The distortion frequencies are 120, 180, 240, and 300 Hz, at 5% applied harmonic
distortion.
The plan is to
RE: Laser Pointers
Laser pointers can indeed be dangerous. However, every one that I have seen
offered for sale in the U.S. comes with prominent safety warnings about
potential eye damage. The retina of the eye is very sensitive to light in
the middle of the 600 nanometer range (bright red). The
Peter,
Excessive energy applied to the capacitors is the most likely culprit. Any
of the following might be the cause:
1) Excessive power supply ripple. Especially with tantalum capacitors,
this will exceed the voltage rating even though the apparent DC level
measured with a meter appears
You might try capacitively coupling the cable shield at one end. We had some
success doing this at a company I worked at some years ago. We mounted the
connector shell to a copper plane at the component side of a thin PCB. the
bottom plane of the PCB was in contact with the chassis of the unit.
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