PSNet
IEC 201-1: 1992 & 1997. as well as EN 60204...
Clause 4.3 (continues) to specify the "usual" general requirements
to be expected from the power delivered to the UUT by a power utility. The
equipment is expected to operate under these conditions. This means that
these disruptions will not interfere with the normal operation of the
machine in any manner which would result in malfunctioning of the machine
including where a failure can have serious economic consequences.
Additionally, the equipment shall be designed to operate correctly under
full load as well as no load conditions when these AC supply interruptions
occur. Further, the purchaser may specify changes or additions to the
requirements as laid out (e.g. whenever custom built equipment is
purchased).
For series manufactured equipment (not custom built) the
manufacturer agrees to meet these conditions when they claim conformance to
204. I usually recommend that they include the list of usual operating
conditions (from Annex B) in the manual to clearly delineate the operating
requirements for the power supplied (along with a lot of other normal
conditions).
My experience is that most equipment will meet these requirements
and that equipment manufacturer's do not usually seek exceptions to the
requirements as listed in 204. I guess that they do not want the hassle of
dealing with their customers in asking for a special AC supply when all of
the rest of the whole world works off of what is available. I'm sure that
there are exceptions, and we'll hear from some of those folks here.
As far as evaluator to these requirements, most electronic power
supplies available for testing (the type that provide for variable
frequency (usually ~50Hz to ~440Hz) and variable voltage (~90V to ~250V for
single phase equipment), etc. either have a built in capability to performs
such supply interruptions or allow for external signals to be supplied to
do so. Common units are 3 phase input with a single phase or 3 phase
output up to 8 or 9kW.
Most EMC labs have line generators with variable input conditions
which can also provide these conditions.
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Peter E Perkins
Principal Product Safety Consultant
Tigard, ORe 97281-3427
+1/503/452-1201 phone/fax
p.perk...@ieee.org email
visit our website:
http://ourworld.compuserve.com/homepages/peperkins
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