Amprobe PQ55A Power-Analyzer - Manual (Page 34)

Harmonic measurement
In this window you can carry out simple harmonic measurements up to the 31st
harmonic.
The total value of the harmonic distortion THD in percent is calculated according
to the following equation:
whereas:
A(f1) = fundamental wave,
A(fn) = harmonic with number n.
The number of harmonics (n) for the calculation of THD can be selected.
Click the (g) [Insert graph] button, to open the window for the
harmonic measurement.
Select the requested input signal in the
(A) window via the arrow keys.
The following input signals can be selected:
A Phase Voltage = voltage on phase L1
B Phase Voltage = voltage on phase L2
C Phase Voltage = voltage on phase L3
A Phase Current = current on phase L1
B Phase Current = current on phase L2
C Phase Current = current on phase L3
☞ Via the I4 input, harmonics cannot be measured.
Select the requested input frequency in the (B) window.
Click the [OK] button to start the measurement.
The values of the 64 sampling values are listed under No.s. In addition, a window
with the representation of the signal curve will be displayed during the measured
time interval of 20 ms (at 50 Hz).
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