The loop resistance tester adopts new power supply technology, which can continuously output large current for a long time, overcomes the shortcomings of the pulsed power supply's instantaneous current, can effectively break down the switch contact oxide film, and obtain good test results. It is suitable for testing the contact resistance value of the main contact of the high and low voltage switch, the DC resistance value of the high and low voltage cable circuit, etc.

Common faults and solutions of loop resistance testers:

1. Failure phenomenon one

The test current of the loop resistance tester is normal, and the micro-ohm value bit displays "1";

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.

Method of exclusion:

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.

2. Failure phenomenon two

Press the "test switch" on the loop resistance tester, the ammeter will display no current, and the micro-ohm meter will display "1";

reason:

The 100A current loop is not connected properly. The test subject's switch was not closed;

Method of exclusion:

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

3. Failure phenomenon three

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

reason:

The 220V AC power supply is not connected, and the fuse is not installed or fused;

Method of exclusion:

Check and rule out. (100A instrument insurance is not less than 6A, then contact the factory to solve it. (Never connect to DC or 380V AC power))

After the loop resistance tester fails, the correct operation method is to interrupt the test work, disconnect the test product, and cut off the power supply. After the equipment is trouble-free, the inspection and test work will be carried out again.