SPEA1 Value Percent Selection Example

SPEA1 has buttons for Percent and Type Selections.
SPEA1 provides the facility to view harmonics upto 55th Level, for both Voltage and Current.

Normally, you will require odd harmonics only, so you can see 3rd, 5th…..55th Harmonic.

If you require even harmonics also, you can set SPEA-1 for this using menu options.

The Menu explained here allows you to see individual harmonics , both as Value and Percentage.

SPEA1 Voltage Value LED Driver Testing THD Measurement example

The Image above   shows a 0.5W LED bulb being tested.

The Sixth Display is showing the Voltage THD of the Third Harmonic, as Absolute Volue.

It is now showing the RMS value of Volt/Amps and Wattage on the first column.

It is showing the %V THD and %A THD in the 4th and 5th display respectively.

It is showing  443.2mV as absolute value of Voltage Thrird Harmonic.

Note the 'm' led is lighted up in this case, just on the left of UP button.





We would like to see the third Harmonic as Percentage terms.

Press the PERCENT Button



SPEA1 Voltage Harmonics as Percentage   LED Driver Testing THD Measurement example

Now it is showing the Voltage Third Harmonic as %.

How is this calculated?

% V THD (3rd Harmonic) =  V THD(3rd Harmonic)/ RMS    X 100

0.183% = 0.443V / 213V   X  100

0.183%  == 0.2%

So, it Matches.




Now, pressing the "THD Type" Button

SPEA1 Amps as Percentage  LED Driver Testing THD Measurement example

We are now seeing that the 3rd Harmonic of Amps is 8.6% of 18.45mA



Now pressing the Percent Button

SPEA1 Amps as Value for Third Harmonic in THD  LED Driver Testing THD Measurement example

It is now showing that the absolute value of Amps 3rd Harmonic is 1.630mA. Note that

the 'm' LED is lighted up, just on the left of the UP button.


% A THD (3rd Harmonic) =  A THD(3rd Harmonic)/ RMS    X 100

8.6% = 1.630mA / 18.36mA X 100

So, it Matches.



If you want to see other harmonics, you can press the UP/Down button for 3rd,5th…55th harmonic one by one.

To get the full Harmonic spectrum, you can press the NEXT[SPECT] button. Since it is not possible to see all the 55 or so values on SPEA-1, you can import this using USB port to your computer and generate a pdf report.

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(Updated: December 10, 2018)