Operation precautions for transformer DC resistance tester

1. Be sure to reset before testing the reverse tapping of the no-load voltage regulating transformer. After the discharge is over, the alarm will stop for more than 10 seconds 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 wait for more than 10 seconds before removing the thread to ensure that the charge is completely discharged.

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.

6. When the test clip is connected to the terminal of the transformer winding, pay attention that the terminal is exposed to the air during the period of time. The surface of the terminal is covered with a layer of oxide film, which may cause unstable or inaccurate measurement results. Attention should be paid to clean the oxide film, or after the test clip is connected to the terminal, twist the test clip a few times to break the oxide film to ensure a good connection.