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Wiring work of loop resistance tester

time:2020/8/6   source:华天电力  reading:832 time

The contact resistance and loop resistance of switch control equipment often need to be tested with a loop resistance tester. The device has a simple structure and is easy to use. It is very popular among power workers. Specifically, the wiring of the loop resistance tester How to do it?

At present, the conventional QJ44 double-arm DC bridge is widely used in power systems to measure the DC resistance of transformer coils and the contact resistance of high-voltage circuit breakers. The test current of this bridge is only mA level, and it is difficult to find the conductive loop of the transformer coil. The defect of reducing the cross-sectional area of the conductor.. When measuring the contact resistance of the conductive circuit of the high-voltage switch, due to the influence of the oil film and the oxide layer between the static and static contacts, the measured resistance value is several times larger, covering the real contact Resistance value.. Therefore, the standard SD301-88 <AC 500KV Electrical Equipment Handover and Preventive Test Procedure> and the new version of the electrical equipment preventive test procedure have a measurement current of not less than 100A for the circuit breaker and disconnector contact resistance to ensure the accuracy of the measurement Sex.

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The loop resistance tester is a combination of digital switching power supply circuit technology and process design. It is suitable for controlling the contact resistance of switching devices and resistance measuring circuits. The test is recommended by DC 100A according to current national standards. It can directly measure the current 100A loop resistance and contact resistance, and carry out digital display. The measuring instrument is accurate and stable, and it may be required for loop resistance testing of high voltage switches for power supply and maintenance department fields.

1. After checking and confirming that the information is correct, turn on a power control switch, and the measuring clamp must be clamped inside the current clamp, otherwise our measurement and research results are not accurate.

2. Press the measurement switch and adjust the current adjustment knob to increase the current to 100A. At this time, the resistance meter displays the value of the measured contact resistance.. If it displays 1, the measured circuit resistance value is out of range; if the measured current is Not 100A, for example. The resistance meter shows Uo, and the actual resistance value is R=100×UoR=IoμΩ).

3. If the wiring is correct, but the current measurement does not reach 100A, the cross-sectional area of the test line should be increased to the current line.

4. After the measurement is finished, disconnect the power control switch, put the test wire clamp away, and put it in the important spare parts box.

If the loop resistance tester wants to play its due performance, it needs to do the wiring work first, and everyone needs to pay extra attention.

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