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AVTMTTR310 Rev 8 May 2016
113
3-Phase TTR310 Test Set Functional Test
A customer may want to make sure that the test set is functioning properly
before testing a transformer. Traditionally, for the transformer turns ratio testers,
a customer performed this test by connecting H1-X1 and H2-X2 test leads. The
1:1 turns ratio was expected to be measured. Additionally, the displayed test
results were interpreted as a test set calibration check.
The 3-phase TTR310 test set is designed and optimized for the transformer turns
ratio testing. It uses a mixed analog-digital technique to provide the high accurate
readings of the tested transformer turns ratio. The test set measurement
approach is based on high impedance input and output transformer voltage
monitoring circuits. The high impedance of the monitoring circuits is optimized
for the accurate transformer turns ratio testing.
When performing a 3-phase TTR310 functional test, the H and X test leads
interconnect the input and output monitoring circuits without a transformer
being connected. Such connection cause an impedance mismatch and, as a result
of the mismatch, the displayed turns ratio reading is not exactly 1:1 as it may be
expected. A customer should be aware that a functional test is not a real
transformer turns ratio test. Due to the intrinsic and inevitable impedance
mismatching, the 3-phase TTR310 functional test readings may be from 0.9980
to 1.0020. The TTR310 functional test readings do not represent its calibration.
It simply shows that the TTR310 test set circuitry functions properly. To check
the 3-phase TTR310 calibration, a customer should use the Calibration Standards
mentioned in Calibration section of the manual.
To perform a 3-phase TTR310 functional test proceed as follows:
1. Turn TTR310 test set power off.
2. Connect H1 lead to X1 lead, H2 lead to X2 lead, H3 lead to X3 lead, and H0
lead to X0 lead. Make sure the leads are properly connected.
3. Turn TTR310 test set power on.
4. After self-test is complete and the main menu screens appear, select 4, and
then select 4 and enter 80 V. On the same menu select 6.
5. When the Main menu appears, select 1.
6. When the Quick test setup menu appears, select 2 and enter 7. The
transformer type entry displays DIAG 07 YNyn0.
WARNING
Do not continue functional test if the QUICK TEST SETUP menu
does not display DIAG 07 YNyn0 transformer type.
Keep the leads, which are energized, clear of ground, and
personnel.
7. Select 3, START TEST on QUICK TEST SETUP menu.
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