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Introduction of three-loop DC resistance tester

time:2020/9/19   source:华天电力  reading:226 time

After the test of the three-circuit DC resistance tester is completed, the transformer sometimes has residual magnetism, causing the situation that it cannot run immediately. After the test is completed, reverse the positive and negative poles of the test line and perform a reverse charge to effectively avoid the above situation. The specific time is flexibly controlled according to the transformer capacity and the size of the test current. To save time, you can press the reset button during the test without waiting for the end of the discharge process, you can directly start the measurement again. When measuring the high-voltage side resistance of the on-load voltage regulation transformer, start the measurement from 1 or 17 resistance gears, and try to choose within the range. Large currents are used to enhance stable performance, and at the same time, the current capacity of the test product should be considered.

Transformer DC Winding Resistance Tester.png

 The interpretation of the measurement results of the three-circuit DC resistance tester also requires certain skills, time experience, different capacity transformers, different measurement methods, different voltage levels, different core structures, etc. The measurement time is different. For the 2400MVA transformer, it will take about 8-10 minutes for each phase to use the assisted magnetic method for its low-voltage side resistance. For single-phase measurement directly on the low-voltage side, it takes 40-50 minutes to measure one phase. For a 150MVA transformer magnetic method, it takes about 3-5 minutes to measure each phase. Without magnetic assistance, each phase takes about 30 minutes. For a transformer with a voltage level of 35KV, the measurement time is greatly reduced. For a three-core transformer below 120MVA, the magnetic method is not used, and the measurement can be performed directly within 20 minutes. For the star connection method, the measurement data is displayed as stable.

The three-circuit DC resistance tester has large output current and light weight. The instrument provides 5 output current options, which can output 10A current. The three-circuit DC resistance tester has a wide measuring range, 0-20kΩ. The three-loop DC resistance tester has a complete protection circuit, more reliable performance, lithium-ion battery power supply, and easy on-site operation. LCD prompt menu operation, easy to use, with sound and LCD indicator discharge alarm, clear discharge instructions, reduce misoperation, suitable for measuring low resistance inductive test products, such as transformers, inductors, large motors and other inductive test products, also Suitable for measuring pure resistive samples with low resistance value. When measuring pure resistive samples, the results can be measured quickly. The DC resistance tester is a high-precision replacement product for DC single and double-arm bridges. It is an ideal instrument for measuring the resistance of various inductive loads such as power transformers and the contact resistance of low-voltage switches, wire and cable or the interface resistance of welding seams. Its measuring speed is more than one hundred times faster than that of electric bridges. The instrument is equipped with a rechargeable battery pack (12V), which can be used for both AC and DC, which is convenient for field and field testing.

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