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Common faults of loop resistance tester

time:2020/9/10   source:华天电力  reading:300 time

The loop resistance tester is refined with advanced high-power switching power supply technology and advanced electronic circuits. It is a special test instrument for high and low switches, cables, wires and weld contact resistance. The current adopts the 100A DC recommended by the national standard GB763 (currently up to 200A), and the contact resistance and loop resistance of the tested product can be measured at a current of 100A (200A). This article mainly introduces the common faults of the loop resistance tester and how to eliminate them.

Micro Ohmmeter.png

Phenomenon one

The loop resistance tester is connected to a 220V AC power supply, the fan is silent, and the "test switch" is pressed once, the ammeter and micro-ohm meter have no display.

the reason

The 220V AC power supply fails, and the fuse is not installed or is blown.

elimination method

 Check and rule out. (100A instrument insurance is not less than 6A, and then contact the factory to solve it. (Do not connect to DC or 380V AC power)

Phenomenon two

To test the loop resistance, press the "test switch", the ammeter shows no current, and the highest bit of the micro-ohm meter shows "1".

the reason

The 100A current loop is not connected properly. The subject switch did not close.

elimination method

Check the test line, reconnect, and re-clamp. Close the switch.

Phenomenon Three

Loop resistance test The test current is normal, and the highest digit of the microohm value displays "1"

the reason

The position of the voltage clamp is wrong. The resistance of the tested loop exceeds 2000. The voltage signal line is broken or not connected.

elimination method

Handle the voltage signal circuit, and clamp the voltage clamp. When the range is exceeded: use a multimeter to measure the voltage values of P1 and P2, and the resistance value = voltage value/current value.

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