To all;
Section 3.2.2(Radiated Emissions - Magnetic Fields) says:
Radiated emissions from the EUT shall not exceed the levels of field
strength obtained from the following equation in the frequency range of
60 Hz through 30 MHz: H = E-51.5dB
In this equation, E is the electric-field
Hi Chris,
Classified area = hazardous location = an area where the atmosphere may be
easily ignitable
Class = type of hazard; Class 1 = gas vapours; 2 = combustible dust, 3 =
ignitable fibers
Zone = Frequency of the hazard; Zone 1 means hazard present frequently or
for long periods; Zone 2
I don't think you can use this directly, but I ran hours of tests on a
tantalum cap at full rated potential while applying large amplitude
microsecond spikes with no hiccups, no heating until I got quite extreme.
The cap was rated at 30 WVDC and I biased it at 28 Vdc, while applying all
kinds of
Group,
Could someone recommend an appropriate UL safety standard to test a Submersible
Aerator-Mixer to.
The device is will be used in the bottom of a lake or other large water body.
It contains a propeller and an AC powered motor.
Thank you for your input.
Barbara Brooks
Wyle
Chris,
This brings back a lot of memories; my first job out of college
was with Factory Mutual Research Corporation (www.fmglobal.com)
doing hazardous location approvals. Instead of reinventing the
wheel (and digging deep into memory), here's a link to an
excellent primer on explosion
Nonetheless, inrush current aside, a 20V Tantalum is considered marginal for a
12V
circuit if reliability is desired. A 60% derating factor was and is a typical
max
for reliability circuits, i.e a 30V min rated cap is recommended. Tantalums
require
additional derating than Al-electrolytics.
Ted,
Good job. But, please, don't stop there. Maybe you should work with Gary
Hogan and between you I see quite a good and useful primer in the works.
Your second statement is the key. But these web sites don't really start at
step 2, more like they start at steps 3 or 4. I am looking for
Chris,
The issue isn't voltage rating; low-ESR caps such as these are susceptible
to excessive charging current at turn-on. At a former employer, we saw
REALLY GOOD, expensive caps used on a computer's 5V bus exploding at
turn-on, even ones rated at 50 volts. Replacing them with cheaper
Chris,
Looks like you're dealing with equipment for use in explosive atmosphere's
legislation/standards. The exact details vary a bit depending on the
world-region (US, Europe, etc...). One of the basic how to determine zones
documents is IEC 60079-10 and its few clones.
Watch out also for
Hi all,
By the way, thank you to the various group members for the responses regarding
the hazardous atmosphere classifications.
One of my colleagues is testing a new design. He has designed a buck-boost
switching converter which has tantalum output capacitors. We have looked at
his
I would add a litle to Rick's insight from my experience.
You may find that Manufacturing appreciates the quality enhancements usually
obtained in the regulatory process (and other test methods such as stress
testing) and would understand the consequences of non-compliance.
Product designers
Hello,
As all the safety standards, IEC 60601 defines the creepage and clearance
distances regarding the working voltage of the considered insulation.
In a switching power supply, designed for medical product, one of my
customer has designed the creepage and clearance distances to be compliant
Hello Chris,
While I can't supply specifics, I expect you can find what you need on
Links available on the Safety Link www.safetylink.com
Once you arrive therein, using your browser's FIND function (Control-F in
most browsers), search on the following terms:
ATEX
Ex Scheme
HAZLOC
Intrinsic
I used to do seminars internal to companies where I worked on this
very subject. Great for people with insomnia.
I can pass along the information for a small fee of, say, $20,000 per page
...
big grin
Regards, Doug McKean
- Original Message -
From: Scott Douglas
To: emc-p...@ieee.org
what a good question. I think I understand your situation, with so much to know
where do you begin?
Numerous websites take the process from step 2 onwards but step 1 is the
concept which may not be obvious to the non-technical person.
It will help if the person has a grasp of basic science,
Hi Rick,
Thank you for the input. I have found the same experience on the penalties
issue. You are correct in the fact that it will be mentioned and not be a
focal point of the article.
Any other comments and suggestions are greatly appreciated.
Incidentally, I would also really enjoy hearing
Regarding my query on medical equipment transformer construction
(EN-60601-1, clause 57.9.4(e)), can I be a bit more specific.
- How were insulation thickness requirements decided, and why is the
thickness requirement lower if insulation is 2-layer rather than
single-layer ?.
- Why are
Hi,
From Appendix A, General Guidance and Rationale, for Clause 57.9
...For reasons of PATIENT safety additional requirements must be applied to
the construction
of such transformers, e.g. restriction of LEAKAGE CURRENTS flowing to
PATIENT CIRCUITS.
57.9.4 e) In transformers with REINFORCED
For what its worth, it has been my experience over the years that management is
turned off by hearing about threats and penalties. That is not to say that
they don't care, and these should definitely be part of your presentation, but
they are looking business building issues. I try to show how
Hi Scott,
I would first show your director the reference in the 2002 NEC Article 90.7
(Page 70-31) Examination of Equipment for Safety. It doesn't get specific
information as what you are asking for, but it does give the reason we have to
do what we do.
From that point on, I'm sure other
Hi Scott,
I am in the process of writing just such an article, directed towards those
within an organization who have, what I would call, a periphery view of
regulatory compliance (directors, purchasing, sales and marketing) and how
it effects them and the company.
I am writing it with your
Cecil,
The nominal supply voltages/frequencies and tolerances in the US, Canada and
Mexico are as follows:
US: 120 V +/- 5%, 60 Hz +/-0.3%
Canada: 120V +5%/-8.3%, 60 Hz +/-0.02%
Mexico: 127V +/-10%, 60Hz +/-0.2%
Therefore, a rating of 100-120V or 100-127 V is acceptable for all
countries, if
Hi all,
I have been asked a question regarding the following:
use in a Zone 1 and Zone 2 classified area. This equipment shall be certified
EEX d and EEx n by a relevant authority (e.g. BASEEFA, CENELEC etc.) and shall
be suitable for Gas Group IIB and Temperature Class T3.
Can anyone
Hello Group,
We have been asked by a customer in Ireland to provide them with a letter
stating our drive to Electronic Rule Compliance; stating the current version of
the software available and when we expect to be fully compliant.
We are a laboratory equipment company and have never seen this
Obviously there is considerable disagreement between myself and what appears
to be the
rest of the group. The positions regarding the consideration of the scanner
as a Class A
device were well thought out. I will bow to the consenses of the group
However, even if the scanner were intended
With regard to transformer construction, CLAUSE-57.9.4(e) of EN-60601-1
General Requirements for Safety of Medical Electrical Equipment requires:-
In transformers with REINFORCED INSULATION or DOUBLE INSULATION the
insulation between 1ary and 2ary windings shalll consist of -
- 1 insulation
Hi,
Does anyone know of any primers on regulatory compliance? Like what
compliance is, why we do it, how does one figure out what standards apply
to a product, and whatever?
Reason I ask is I had these questions posed to me by one of our directors.
He wants to learn about compliance. I was
John,
I have to agree with Gary on this one. While the scanner requires some sort
of host computer and connects via SCSI port, the host need not be a
Personal Computer of the sort destined for residential use. In a former
life, my employer made scanners and recorders for the graphics arts
Hi John,
Regarding Audio Product-Compulsory Standards for Thailand;
TIS 1195-2536 (Mains operated electronic and related apparatus for household
and similar general use: safety requirements) covers home audio and is
translated/derived from IEC 60065. As you rightly mentioned, it has an
So, what will happen to PLC (PowerLine Communication) in US ? I
know an application called CEBus and they operate in the frequency
band 100kHz-400kHz. Those folks using CEBus will not meet the new
conducted emission requirements.
Maybe, that sort of equipment is not within the scope of FCC
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