>I realise that none of the above give much comfort to manufacturers of
>domestic or consumer products, but maybe a computer manufacturer could
offer
>a version without PFC only for use in installations that have a dedicated
LV
>supply.
No, the big problem is for manufacturers who make commercial and light
industrial equipment that are under
16A and are connected to the public power mains. This is the majority of
commercial equipment.
As was mentioned previously, the harmonic and flicker standards are
considered by many to be "skewed"
standards because they were heavily influenced by the power industry
virtually to the exclusion of all other
data and input.
The issue is not whether harmonics and line votage variations are a
problem. The issue is to what extent they
are a problem. And until these standards become "unskewed" and all data is
weighed, these two "tainted"
standards will not be believeable.
Bob Heller
3M Product Safety, 76-1-01
St. Paul, MN 55107-1208
Tel: 651- 778-6336
Fax: 651-778-6252
================================================================================
CherryClough@ao
l.com To: [email protected]
cc: [email protected]
01/24/2002 (bcc: Robert E.
Heller/US-Corporate/3M/US)
11:58 AM Subject: EN 61000-3-2
applicability and let-outs
Please respond
to CherryClough
Dear John
I understand the following statements to be true.
Please make corrections / comments where necessary.
1) EN 61000-3-2 only applies to equipment consuming up to 16A/phase, and
there are no mandatory harmonic limits in the EU (yet) for higher-powered
equipment, other than what the power supplier might impose.
So EN 61000-3-2 is optional for equipment consuming >16A/phase.
2) EN 61000-3-2 currently has a let-out for "professional equipment" that
consumes more than 1kW, so its application is optional for that category of
equipment too.
This could exclude many of the larger products sold solely for commercial
and/or industrial use from EN 61000-3-2.
(Maybe the combined air-conditioner / personal computer may not be such a
bad
idea if it gets consumption up above 1kW!).
3) The 'public low voltage supply' is a 4156/230V supply with more than one
consumer connected. Large plants or office building often take their power
at
MV (11kV or more) and transform their own LV supply with their own
distribution transformer - creating a 'private' low voltage supply
dedicated
for their own use.
EN 61000-3-2 is optional for any equipment sold solely for use on such
dedicated low voltage supplies.
Privately-generated LV supplies ditto.
4) My copy of EN 61000-3-2 has a paragraph at the end of its Scope section
that says:
"Special equipment, which is not widely used and is designed in such a way
that it is unable to comply with the requirements (limits), may be subject
to
installation restrictions. The supply authorities shall be notified as
authorization may be required before connection."
So custom-made or low-volume manufactured equipment (even if under
16A/phase)
does not have to comply with EN 61000-3-2, as long as their users check
with
their power suppliers that they are OK to be connected.
Maybe they could agree to deal with any harmonic issues at site-level, by
installing an active harmonic cancellation unit.
Regards, Keith Armstrong
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