The Harmonics and limits form displays the calculated individual harmonics of the input current and compares them to the limits described in the IEC 6100-3-2.
Click the Chart button to display the Fourier harmonics chart.
For LED lamps with power above 25W the individual harmonics must be below the limits defined in the standard IEC61000-3-2 for class C equipment. If the power is below 25W then the class D limits are applicable.
In the chart the red lines represent the limits according to the standard. The software will automatically select the correct class according to the output power. For class C the limit for the third harmonic was fixed at 27% (assuming a power factor of 0.9).
Please note that the second harmonic is not represented in the chart (for class C). This is because the second harmonic depends on the controller and on the AC source. Contrarily to the other harmonics on the chart, where the design of the power supply (size of bulk capacitor, kp, VOR) will change the harmonics considerably, the second harmonic will have a much smaller dependence because it only is present if there is no half-wave symmetry.
At the Fourier Harmonics Chart dialog box, you can do the following actions:
- saves the chart as .bmp file.
- prints out the chart.
- shows or hides the chart legend.
- Opens the Graph Options dialog box where you can customize the chart.
The Series tab allows you to hide/show graphs and specify their color and line style.
The Common tab lets you to edit the value range for X and Y axes and the chart title.
The Colors tab allows you to adjust the colors and styles for the chart components.