Datakom DKM-409 PRO AT, Руководство пользователя, Страница: 14 / 66

DKM-409 Pro AT User Manual Rev_02 Firmware V-2.5
Structure: Isolated, internal current transformers
Measurement method: True RMS
Sampling rate: 8192 samples/sec.
Harmonic analysis: up to 49th harmonic
CT secondary rating:
5A
Measurement range: 5/5 - 25000/5A minimum
Input impedance: 15 mili-ohm
Burden: 0.375W
Maximum current: 6A continuous
Measurement range:
0.001 to 6A AC
Display resolution: 0.1A
Accuracy: 0.5% + 1 digit
Isolation: 1000VAC/1minute from all other terminals.
Withstand: 100A-AC for 1 second
SELECTING THE CT RATING AND CABLE SECTION:
The load on a CT should be kept minimum in order to
minimize phase shift effect of the current transformer.
Phase shift in a CT will cause erroneous power and
power factor readings, although amp readings are
correct.
Datakom advises CT rating to be selected following this
table for the best measurement accuracy.
SELECTING THE CT ACCURACY CLASS:
The CT accuracy class should be selected in accordance
with the required measurement precision. The accuracy
class of the Datakom controller is 0.5%. Thus 0.5% class
CTs are advised for the best result.
CONNECTING CTs:
Be sure of connecting each CT to the related phase input with the correct polarity. Mixing CTs between
phases will cause faulty power and pf readings.
Many combinations of incorrect CTs connections are possible, so check both order of CTs and their
polarity. Reactive power measurement is affected by incorrect CTs connection in similar way as active
power measurement.
3.3. AC CURRENT INPUTS