3.4.12 Z, ZB - Impedance
The Winding Impedance test measures the impedance of a selected winding using specified voltage (or current) and frequency conditions. An AC voltage is applied across the winding under test and the complex impedance is determined from measurement of the test voltage and the flowing current. The Z result is the magnitude of this impedance.
This test is normally used for audio & telecommunication transformers to check the impedance presented to the transformers input and output.
On selecting "Z Winding Impedance" from the 'available tests' window, the following dialog box is displayed:
To program the test:
- Enter the value of voltage (or current) for the signal and the required frequency of the test. (If in doubt, refer to Chapter 7 - ‘Test Conditions’, which lists recommended test conditions.)
Note also that the Measure button may be used here as outlined in section 3.9.
- Select the integration time required. '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 terminal names between which the impedance is to be measured. See terminal selection.
- Set the impedance limits.
||Enter a nominal value and then the limits as negative and positive
||Enter minimum and maximum values.
||Enter just a minimum value.
||Enter just a maximum value.
- For the impedance with bias test, you may also select a DC bias current
- Select OK. The test specification will then be displayed in the program window.