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12.1 Voltage Fluctuation and Flicker Measurement Function
12-2
• Data Update Interval
The display update interval in voltage fluctuation and flicker measurement mode is 2 s.
• Limitations on the Function and Measurement Function
In voltage fluctuation and flicker measurement mode, the internal computation is
different from other measurement modes in order to achieve measurements
conforming to the IEC standard. Therefore, some functions such as waveform or bar
graph display on the screen, store function, motor evaluation function (option) cannot
be used in this measurement mode. In addition, some measurement functions such
as integration and efficiency computation cannot be carried out. For a list of functions
with limitations and measurement functions that cannot be measured, see appendices
10 and 11 in the User's Manual IM WT3001E-01EN.
• Saving the Voltage Fluctuation and Flicker Measurement Data
The voltage fluctuation and flicker measurement data cannot be saved on this instrument.
Use the Harmonic/Flicker Measurement Software and save the data on the PC.
• For details on the power supply for testing, test conditions, and
terminology, see IEC 61000-3-3.
• Terminology
Flicker
Flicker refers to the unstable impression perceived by the human eye that is induced
by the fluctuating intensity or spectral distribution of light. It expresses the irritation that
the people receive due to the fluctuation of brightness.
Steady-state condition
A condition in which the rms voltage for each half period is stable for 1 s or more.
Relative steady-state voltage change dc
A value obtained by dividing the difference between two steady-state voltages before
and after a single voltage fluctuation by the rated voltage expressed as a percentage.
For example, for a power supply with a rated voltage of 230 V, the relative steady-state
voltage change is as shown below if the steady-state voltage before the fluctuation is
231 V and that after the fluctuation is 232 V.
232 - 231
× 100 (%) = 0.43%
230
Note
•
If no voltage fluctuation occurs in the measurement period, dc is zero.
•
IEC 61000-4-15 specifies if a steady-state condition does not occur during the measurement
period, it is considered to be a fluctuating condition. The measured value of dc is displayed
as Undef (undefined, IEC 61000-4-15 Ed1.1) or 0 (IEC 61000-4-15 Ed2.0), and the
judgment is displayed as Error (IEC 61000-4-15 Ed1.1) or Pass (IEC 61000-4-15 Ed2.0).
Maximum relative voltage change dmax
• For IEC 61000-4-15 Ed1.1
A value obtained by dividing the difference between the maximum and minimum
values in a single voltage fluctuation
percentage.
• For IEC 61000-4-15 Ed2.0
The absolute value of the difference between the maximum value and the value
in the previous steady-state condition is compared with the absolute value of the
difference between the minimum value and the value in the previous steady-state
condition in a single voltage fluctuation.
larger of the two values by the rated voltage expressed as a percentage.
* Condition between two steady-state conditions.
*
by the rated voltage expressed as a
*
dmax is the value obtained by dividing the
IM WT3001E-51EN
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