3.4.6 Quality Factor
To test for Q factor, an ac voltage is applied across the selected winding. The voltage across and current through the winding are then measured using harmonic analysis. The measured voltage is divided by the current to obtain a complex impedance, from which the Q factor is calculated.
On selecting ‘QL Q Factor’ from the Available Tests window, a dialogue box will be displayed.
To program the test :
- Enter the signal and frequency required for the test.
Note that the signal is normally entered as a voltage by selecting the 'mV' or 'V' button; but you may optionally enter it as a current by selecting the 'mA' button.
(If in doubt, refer to Chapter 7 - ‘Test Conditions’, which lists recommended test conditions based on the values of winding inductance.)
Note also that the Measure button may be used here as outlined in section 3.9, with the combinations of test parameter specification shown in the following table:
| Signal |
Specified voltage |
Specified current |
Auto |
| Frequency |
Specified |
Specified |
Specified |
Normally, the Q factor test would follow an inductance test on the same winding. Using the same test conditions for both tests will speed the execution of the program.
- Select (mouse click the button) the integration time you require.
'Medium' is the default setting. 'Long' will give more stable readings (for tighter limits) at the expense of an increased test time, and 'Short' will test at the maximum speed, but may give a slightly noisier reading.
- Enter the high and low terminal names. Use the mouse to pull down the menu along side the fill-in box, and double click to select the terminal.
- Select (mouse click the button) the type of limits you require and enter the values.
| % |
Enter a nominal value and then the limits as negative and positive
percentage values. |
| >< |
Enter minimum and maximum values. |
| > |
Enter just a minimum value. |
| < |
Enter just a maximum value. |
| Note that the Measure button may be used here as outlined in section 3.9. |
- Select OK. The test specification will then be displayed in the program window.