I was wondering if anyone was aware of any guidance documents that provided
acceptable levels of uncertainty when conducting various tests. The
specific measurement that I am interested in this case is temperature
measurements, but I would be interested in seeing other guidance for other
measureme
This is a question that goes back to the beginning of time; or at least the 35
years I’ve been on the job. And I’ve never heard a good reason for either side
of the argument. You don’t want unqualified people trying to wire a Plug onto a
power cord and you don’t want to ship a plug that will mos
Kevin,
Most certifying agencies will provide information on their expectations for
measurement uncertainty. The EMC people of this world can go on for ages
about the topic, you will almost always see a workshop on this at the
annual EMC symposium. For safety testing this usually does not come in
>From this side of the Herring Pond, it looks as though a law that requires a
>plug is sensible for consumer electronics and household appliances (which is
>the law in Europe), but has been extended, through excess of zeal no doubt, to
>other sorts of product that can be expected to be installed
Mr. Robinson,
Nothing said necessarily represents the opinions or policies of my employer(s).
Agree with Doug Powell's comments.
Methinks this is a bit more of an internal policy for the NCB/NRTL than what
has been specified by regulation or standards. The conformity assessment
bodies where m
Hi Brian,
We are talking about the product with rated current > 200A and special
industrial plug and special location.
Why such restrictions? In EU it is recommended to have permanent connection to
mains.
Best regards,
Bostjan
On 20. sep. 2016, at 17.47, Kunde, Brian
mailto:brian_ku...@lecot
Hi Kevin!
You didn't specify the measurement method, but if you use thermocouples,
does your lab use use OD5012 (used to be called OP-108 and 109)? It is
also from the IECEE but gives guidance on how to prepare and use
thermocouples. You asked for guidance on acceptable tolerances, which this
doe
All conductors can be affected by EM fields. Thermocouples containing iron,
like Type J and K, are more susceptible than others.
I’ve experienced some susceptibility of Type T thermocouples in some instances.
I don’t have any experience with, “The J and K type thermonuclear probes.”☺
FWIW, even
I forgot to copy the list on my response to Bostjan, but essentially my
assumption was that Article 645 provides a significant exceptions to other
parts of the NEC such as: prohibition on running cables through holes in
floors (see 400.8), and prohibition of running non-plenum rated cables in a
pl
I was wondering if anyone was aware of any guidance documents that provided
acceptable levels of uncertainty when conducting various tests.
I didn’t know what “uncertainty” is, so I did a Google search and found this
reference:
https://www.wmo.int/pages/prog/gcos/documents/gruanmanu
ISO, International Standardization Organization, Guide to the Expression of
Uncertainty in Measurement, GUM
ISO, General Requirements for the Competence of testing and calibration
laboratories, ISO 17025
http://www.bipm.org/en/publications/guides/gum.html
Brian
From: Richard Nute [mailto:ri...@
Measurement uncertainty depends on instruments used, method used etc. Each lab
has to do calculation of measurement uncertainty for particular method.
Measurement uncertainty becomes critical when results are close to the limit.
High uncertainty means you have more chance to be in »a grey area«
Dear experts I again need your opinion on below issue.
Customer was asked for development of power supply which will be used to supply
a server in data centre. Input to power supply is defined as 750VDC.
Unfortunately no information is available how this DC supply voltage is
generated and refe
in general, the test standards prescribe the accuracy / type of equipments and
method to be used for testing. This means that measurement uncertainty has been
specified indirectly. In such cases, where we are following these guidelines,
the pass/fail decision can be taken based on the limits gi
Can it be that the output is indeed floating and nominally +/- 375V? If you use this, some sort of fault detection would be required to shut down if either end point becomes grounded. Sometimes this get tricky if the fault detection can be shown to fail in an unsafe way. If achieved, you can use
Hi Doug,
Thank you for your tip. I was already thinking of it, however I believe this is
allowed only if middle point of supply has reference to earth.
Best regards,
Bostjan
From: Doug Powell [mailto:doug...@gmail.com]
Sent: Wednesday, September 21, 2016 6:17 AM
To: Boštjan Glavič ; EMC-PSTC
Hi Bostjan!
You might be able to use 60950 or (UL1012?) anyway; I know the scope says
"Mains or Battery powered up to 600V", but I think the focus of that limit
(vs the 1000V limit in the LVD for example) might be on just Mains powered
circuits, because 600V is the delineation point between "Low Vo
Hi Ken,
UL1012 has the same limitation as 60950-1.
IEC 61010-1 is not OK since it is not a laboratory equipment or measuring
equipment.
IEC 62477-1 has also limitation in the scope however limits are 1000Vac and
1500VDC.
Best regards,
Bostjan
From: IBM Ken [mailto:ibm...@gmail.com]
Sent: Wedn
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