40A transformer DC resistance tester test operation method and matters needing attention

When we are choosing the 40A transformer DC hipot test equipment , we not only understand the functional characteristics and parameter performance of the 40A transformer DC resistance tester, but the most important thing is to understand the test operation method and attention of the 40A transformer DC resistance tester. Matters, whether the operation is simple when in use, and avoid some unnecessary misunderstandings.
Please refer to the following description for the test operation method and precautions of the 40A transformer DC resistance tester:
1. Wiring of 40A transformer DC resistance tester: Connect the tested product to the test terminal of the machine through a dedicated cable, the connection is firm, and the ground wire is connected.
A. Directly measure the wiring. See Figure 2: 

B. The wiring of assisted magnetic method is shown in Figure 3~5 (applicable to Y(N)-d-11 connection group)

Figure 3, Figure 4, Figure 5 are the wiring method of measuring low voltage Rac, Rba, Rcb respectively
2. Current selection: turn on the power switch (I on the switch is on, O is off) and all current values ​​will be displayed on the display. At this time, you can select the preset current of the tested product through the selection key, and press the selection key every time , The cursor will scroll between the current values ​​of 5A, 10A, 20A, and 40A.
3. Test: After selecting the current, press the confirm button to start the test, and the meter will indicate the selected current value at the same time. After pressing the confirm button, the display shows “Charging”, and after a few seconds, it shows “Testing”, which means that the charging is complete. Enter the test state, a few seconds later, the measured resistance will be displayed. (The selected current value and the measured resistance value will be displayed on the screen at the same time, I=“ ”A; R=“ ”mΩ/Ω)
4. After the test is completed, press the “reset” button, the transformer DC resistance tester power supply will be disconnected from the windings, discharge at the same time, sound an alarm, and the ammeter will return to zero. At this time, the display screen will return to the initial listening state, and the discharge sound will end. , You can re-wire to perform the next measurement or remove the test line and power line to end the measurement.
40A transformer DC resistance tester test operation method and matters needing attention:
1. It must be reset before testing the reverse tapping of the no-load voltage regulating transformer. After the discharge is over, the alarm sound stops before the tapping point can be switched.
2. Before removing the thread, be sure to wait for the alarm to stop after the discharge is over, and then remove the thread.
3. When selecting the current, please refer to the range in the technical index column, and do not use over range or under range. When the range is exceeded, the instrument is always in the “charging” state because the current does not reach the preset value. When the range is under-range, “current too small” is displayed. When these two states appear, confirm the range and select the appropriate current for testing.
4. Pay attention to the range when using the magnetic method. Because two high-voltage coils are connected in parallel and one is connected in series, 1.5 times the resistance of the high-voltage coil is added to the entire test loop, which should be included when selecting the range. If the output current cannot reach the set value or the output current is unstable if the range is exceeded.
5. When the short contacts of the three wires of the magnetic assist method are removed after the discharge is completed, there may be residual current, and may spark and discharge when removed. This is a normal phenomenon.