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Notes for transformer dc resistance tester

time:2020/5/13   source:华天电力  reading:303 time

Dc resistance test of transformer windings is an indispensable test item after transformer handover, maintenance and replacement of tap switch. Usually, it is time-consuming and arduous to measure the dc resistance of transformer windings and high-power inductive equipment with traditional methods (bridge method and voltage drop method). In order to change this situation, shorten the measurement time, reduce the workload testers, the company developed a rapid dc resistance tester (hereinafter referred to as the transformer dc resistance tester), USES the new type of power supply technology, with stable performance, fast measurement speed, small volume, convenient use and high accuracy of measurement, data repeatability, perceptual equipment and large power transformer winding dc resistance measurement is an ideal device.

Transformer DC Winding Resistance Tester.png

1. The transformer must be reset before the reverse tap of the no-load voltage regulating transformer. At the end of the discharge, the alarm stops for more than 10 seconds and then switches the click point.

2. Before removing the wires, wait for the alarm sound to stop after discharge. It is better to wait more than 10 seconds before removing the wires to ensure the complete release of charge.

3. When selecting the current, refer to the range in the technical indicator bar, and do not exceed or fall below the range. If it goes out of range, the instrument is always "charged" because the current cannot reach the preset value. When the range is low, it says "current is too low". When both states occur, confirm the range and select the appropriate current for the test.

4. When using magnetic assistant method, please pay attention to the measurement range. Since the high voltage coil is in parallel with the series coil, 1.5 times the high voltage coil resistance is added to the entire test circuit and converted to the measurement range. If the output current does not reach the set value or exceeds the range, the output current is unstable.

5. It is normal to remove the short-circuit contact of the three-row magnetically assisted method after discharge, when there may be residual current, and the short contact of the magnetically assisted method can be ignited and discharged for three times.

6, when the test fixture and terminal of the transformer winding connection, pay attention to the terminal in long time exposure to air, the surface oxidation film, the terminal can lead to instability or inaccurate measurement results, therefore, should pay attention to clean oxide film, when wiring or after the test fixture connected to the terminal, the test fixture to reverse several times, cross off oxidation film, to ensure the good connection of receiving.

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