Making The Measurements using the DataSYS 7100 Power Analyzer
In order to make the measurements for harmonic currents and the power factor of the equipment under test the following equipment is required:
DataSYS 7100 Power Analyzer
PB60 (x100) Voltage probe on CH1
PR30 Current clamp on CH2
The Power Analyzer has two modes. Analyzer Mode and DSO Mode. The 7100 should be in Analyzer Mode before making measurements.
Obtaining The Results
Once the machine is switched on press the Special menu button and select the option marked Analyzer. Here you are faced with a number of options but first you will need to set the Class of equipment to be tested. Pressing the button marked Select Class allows you to cycle through the four classes. Once you have selected the correct class you can make measurements of the Power Factor whilst displaying the Voltage and Current waveforms, look at the harmonic content of the Current along with the limits for the standard in that Class of equipment, or show on screen and print out a test report page showing each of the measured Harmonic values and the limits for the standard in that Class of equipment along with an automatic PASS/FAIL rating. Just press the button for the measurement which you wish to make.
Power Factor
This screen shows the Voltage and Current waveforms so that you can actually see the shape of these and allows the distortion of the Current waveform to be easily seen. At the same time the values of Real and Apparent Power and the Power Factor are automatically calculated and displayed so that the effects of any Power Factor Correction which you apply can be seen immediately by its effect on the waveforms themselves and the value of the Power Factor calculated. By adjusting the zoom (both x and y) you can look in detail at the waveforms.
Harmonics
Pressing this button takes you to the screen showing the Current harmonics with the limit line. The limit line which is shown is the standard for the particular Class of equipment under test as selected previously and is calculated live according to the standard (See Appendix A) so that as the Voltage and Current changes due to any adjustments made, the limit line will remain true to the standard. Any harmonic which is within the standard will appear below the line within the shaded area and any harmonic which is outside the standard (i.e. causes the equipment to fail the test) will show above the shaded area. Pressing the Next Peak and Previous Peak buttons allow you to quickly step through the harmonic peaks with the cursor so if one particular harmonic is of interest the exact amplitude and frequency of this harmonic can be analysed and shown. The zoom facility is again available in order to give closer inspection of the harmonic content of the Current. The values of Real and Apparent Power and Power Factor are again calculated and displayed live so the link between Current Harmonics and Power Factor can be seen.
Test Results
This button takes you to the Test Results screen which shows a table of results of the Current harmonics test (i.e. the measured values at each harmonic, the limit for this value to meet the standard, and an automatic PASS/FAIL rating) complete with the Class of Instrument which this test was for and the Real Power being used by the unit under test. The table is split across four pages with ten harmonics on each page and pressing the button marked with the harmonic numbers group allows you to step through the pages, 1-10, 11-20, 21-30, 31-40. By pressing the Plot button at any time in the Power Factor, Harmonics or test result screen, the display shown at this time will be plotted to the internal plotter or the external printer depending on the plot configuration. When the Test Results screen is showing, hitting the "Plot Results" soft key allows the information on all four Test Result pages to be printed in a long table for easy viewing and archiving (i.e. 1 - 40th Harmonics).
Updated 17 March 1998