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Notes on operation of DC resistance tester

time:2020/7/16   source:华天电力  reading:974 time

Note for DC resistance tester:

1. Be sure to reset before measuring the reverse tapping of the no-load voltage regulating transformer. After the discharge is completed, the alarm sound stops for more than 10 seconds before the tap point can be switched.

2. Before disconnecting the wire, be sure to wait for the alarm to stop after the discharge is completed. It is best to wait for more than 10 seconds before removing the wire to ensure that the charge is fully discharged.

Transformer DC Winding Resistance Tester.png

3. When selecting the current, refer to the range in the technical index column, and do not exceed the range and under range. When over-range, because the current does not reach the preset value, the instrument has been in the "charging" state. When the under-range is displayed, "current is too small" is displayed. When these two states appear, confirm the range and select a suitable current for testing.

4. Pay attention to the range when using the magnetic assist method. Because two high-voltage coils are connected in parallel and one is connected in series, 1.5 times of high-voltage coil resistance is added to the entire test circuit, which should be converted when selecting the range. If the output current cannot reach the set value or the output current is unstable when the over-range is used.

5. The short-circuit points of the three wires of the magnetic assist method may have residual current when the wire is disconnected after the discharge is completed, and it may spark and discharge when removed. This is normal.

6. When the test clip is connected to the leading end of the transformer winding, pay attention to the long-term exposure of the leading end in the air, the surface of the leading end is covered with an oxide film, which may cause unstable or inaccurate measurement results, so when wiring Pay attention to cleaning the oxide film, or after the test clip is connected to the lead-out end, twist the test clip a few times to break the oxide film to ensure a good connection.

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