Amprobe ACD-51HP Power-Quality-Clamp-Ons - Manual (Page 21)

ACD-51HP - ACD-56HPQ
4.3.7. Measurement of current harmonics (ACD-56HPQ only)
WARNING
Before attempting any measurement disconnect all the test leads from the
circuit under test and from the meter's input terminals.
CORRECT INCORRECT
Fig. 11: harmonic current measurement
1. Select the “
A
” position.
2. Press the FUNC key and keep it pressed at least 1 second until symbol “THD%” is
displayed.
3. Open the jaws and clamp only one cable. Pay attention to the alignment marks (see
paragraph 4.1.2. and Fig. 11). The instrument displays the Total Harmonic Distortion
value of the input signal. The symbol “THD%” is displayed. See chapter 0 for the
parameter’s definition.
4. With the H ↑ and H↓ keys you can cycle through all available harmonic values from the
1 st to the 25 th order. On the secondary display is shown the order of the harmonic
whose percentage value is displayed on the main one (ex. H3% means third harmonic).
5. Press the FUNC key to switch to the absolute harmonics’ values displaying (from 1 st
to 25 th order). The secondary display indicates the order of the harmonic whose
absolute value is displayed on the main one (ex. H3 means third harmonic).
6. If the display is difficult to read, press D-H key to hold the measured value. To disable
this function, press the D-H key again.
7. If the measurement is being performed in a dark environment, press and hold the
key for 1 second to activate the backlight. It automatically turns OFF after 5 seconds.
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