3.4.20 ANGL - Impedance Phase Angle
The Impedance Phase Angle test can measure the impedance of a selected winding using specified voltage (or current) and frequency conditions, and then reports the equivalent impedance phase. An AC voltage is applied across the winding under test and the complex impedance is determined from measurements of the voltage across the winding and the current flowing through it. The ANGL result is the phase of this complex impedance, it is the phase angle between the voltage and current.
This test is normally used for audio & telecommunication transformers along with the Z (impedance) test to check the complex impedance presented to the transformers input and output.
On selecting “ANGL Impedance Phase Angle” from the ‘available tests’ window, the following dialogue box will be 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. Note: you must specify the frequency when using the ‘Measure’ button in the ANGL test.
- 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.
- Enter the phase limits.
For phase tests, the convention of the result returned by the AT depends on the minimum limit requested. If this limit is >0 the result returned is between 0° and 360°. If the minimum limit is >-180°, the result returned is between –180° and 180°, otherwise the result returned is between –360° and 0°. This is done to ensure continuity of results and ease of setting limits irrespective of where the phasor diagram is being checked.
- Select ‘OK’. The test specification will then be displayed in the program window.