ALL-TEST PRO ATPOL II, Руководство пользователя

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Time and Capacity Measurements in PSM
The Data Setup window allows you to review and change many of the time and capacity
measurements. The time capacity of the consumption log, the record capacity of all the logs and the
programmed start and stop time of monitoring (if one exists) can be reviewed and changed.
The number of records used in any of the log types can be determined by attempting to receive the log
data from an attached ATPOL II.
The measurements of time and capacity presented on the ATPOL II can also be displayed in PSM by
using the remote control feature.
Harmonic Measurements
French mathematician Jean Baptiste Fourier determined 150 years ago that any periodic waveform can
be mathematically defined to be the sum of a fundamental frequency equal to the periodic rate and
additional frequencies that are multiples of the fundamental frequency. Thus any repeating waveform
that does not appear to be a pure sine wave can be replicated by adding a collection of sine waves of
varying frequencies, phases, and peak amplitudes. Since the frequencies are exact multiples
(harmonics) of the fundamental, the waveform could be considered to be distorted from a pure sine
wave by the addition of harmonic frequencies. The total harmonic distortion provides an accurate
measure of how distorted from a pure sine wave, a waveform is.
There are several related measures of interest:

Fundamental frequency

Harmonic frequency

Harmonic number

Harmonic amplitude

Harmonic phase angle

THD (total harmonic distortion)

K factor.
The fundamental frequency is the first harmonic. It is discussed in the
Frequency Measurements
section. The harmonic frequencies are the frequencies that are multiples of the fundamental frequency.
For instance the 7
th
harmonic of 60 Hz is
7 60 420 Hz
 
. In this case, “7” is the harmonic number of
420 Hz in a 60 Hz system.
The RMS value of a harmonic frequency is its harmonic amplitude. They can be expressed as relative
to the amplitude of the fundamental frequency or as an actual RMS amp value. For instance if the
fundamental frequency has a current of 120 amps and the 5
th
harmonic has an amplitude of 30 amps,
then the 5
th
harmonic has a magnitude of 30 amps or a relative magnitude of 50%.
The harmonic phase angle is the number of degrees that it leads the fundamental frequency.
Comparing the difference in the phase angle between voltage and current of a given harmonic allows
you to determine the “direction” of the harmonic.