PSNet,
Rich is absolutely correct... and this use of the 990 network is
being recommended as an update to 950 - in a future update to the
standard... The advantage of this network is that one does not have to look
at each harmonic individually; the network does that and sums them into the
result which is read on the meter... further, the measured reading remains
the same as the low frequency value allowed - 0.7mApeak/0,5 mArms,
5.0mApeak/3.5mArms, etc... so the evaluator always looks for a fixed value
and doesn't have to worry about how much of which harmonics... commercial
meters utilizing this network are available, altho I always like to look at
the waveform too because of the controversy over peak vs rms
measurements...
:>) br, Pete Perkins
Convenor, IEC TC74/WG5; IEC 990
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Peter E Perkins
Principal Product Safety Consultant
Tigard, ORe 97281-3427
+1/503/452-1201 phone/fax
[email protected] email
visit our website:
http://ourworld.compuserve.com/homepages/peperkins
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