User Manual

The menu system
Correction VAr
(CVArs). This parameter displays the values of VArs required to
correct the average power fac tor to a target power factor. The target power fa ctor
is entered under the integrator setup screen under CVArs Power Factor.
The correction will calculate the necessary VArs to provide a phase shift to reach
a target power factor. It does not compute the total VArs. If a poor power factor is
completely due to distortion, no amount of phase lead or lag will improve it.
PWM Motor mode
PWM Motor mode allows accurate measurements of PWM motors. It is designed
to overcome the difficulties associated with making measurements on the complex
waveforms found on the motor drive. High frequency sampling is combined with
digital filtering to reject the carrier frequency and extract the motor frequency
while still using pre-filtered data for power parameters.
After selecting PWM mode, select the frequency range of the motor frequency
(not the carrier frequency) under the Inputs → Frequency Source → Frequency
Range menu.
When in PWM mode, the maximum motor frequency is limited to 900 Hz, even if
a higher frequency range is selected.
The sele ction of the frequency range will impact the rate at which results are
returned. The update rate for all the channels is set in the System Configuration
menu. (See page 60, Update rate.) However, if the frequency range in PWM
mode is set to either 1 – 100 Hz or 0.1 – 10 Hz, then the rate at which results are
returned for that group is altered per the table below:
Table 4: Effects of f requency range settings i
nPWMmode
Update rate
(seconds)
>10 Hz
<900 Hz 1 – 100 Hz 0.1 Hz – 10 Hz
0.2 0.4 2.4 20.2
0.3 0.3 2.4 20.4
0.4 0.4 2.4 20.4
0.5 0.5 2.5 20.5
0.6 0.6 2.4 20.4
0.7 0.7 2.1 20.3
0.8 0.8 2.4 20.8
0.9 0.9 2.7 20.7
1.0 1.0 3.0 21.0
1.1 1.1 2.2 20.9
1.2 1.2 2.4 20.4
1.3 1.3 2.6 20.8
1.4 1.4 2.8 21.0
1.5 1.5 3.0 21.0
1.6 1.6 3.2 20.8
46 PA3000 Power Analyzer User Manual