AEMC 205 - Measurement of the Level of Harmonics (Thd) and; The Frequency of the Fundamental (Network); Measurement of THD and Frequency of the Fundamental (V); Measurement of THD and Frequency of the Fundamental (A)

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3.14 MEASUREMENT OF THE LEVEL OF HARMONICS (THD) AND
OF THE FREQUENCY OF THE FUNDAMENTAL (NETWORK)
The device measures the total harmonic distortion with respect to the
fundamental (THD
f
) and the total harmonic distortion with respect to the true
RMS value of the signal (THD
r
) in voltage and in current. Similarly, it determines
the frequency of the fundamental by digital filtering and FFT, for network
frequencies of 50, 60, 400, and 800Hz.
3.14.1 Measurement of the THD and the Frequency of the
Fundamental (V)
1. Set the switch to and press and hold the button for (>2s). The
THD
f
symbol is displayed. To select THD
r
, press the button again.
The THD
r
symbol is displayed. To select the frequency of the
fundamental, press the button again. The Hz symbol is displayed.
2. Connect the black lead to the COM terminal and the red lead to the “+”
terminal.
3. Place the test probes or the alligator clips on the terminals of the circuit
to be measured.
The measurement is displayed on screen.
3.14.2 Measurement of the THD and the Frequency of the
Fundamental (A)
1. Set the switch to and press and hold the button for (>2s). The
THD
f
symbol is displayed. To select THD
r
, press the button. The
THD
r
symbol is displayed. To select the frequency of the fundamental,
press the key again. The Hz symbol is displayed.
2. Clamp the jaws around the conductor to be measured.