The loop resistance tester is designed with a combination of high-frequency switching power supply technology and digital circuit technology. It is suitable for measuring loop resistance of switch control equipment. The test current adopts the DC 100A and 200A recommended by the national standard. The loop resistance can be measured directly at a current of 100A, or the loop resistance can be measured directly at a current of 200A, and the test results are displayed in numbers. The instrument is accurate in measurement and stable in performance. It meets the requirements of on-site high-voltage switch maintenance and high-voltage switch factory loop resistance testing in electric power and power supply departments.

The instrument is suitable for high-precision measurement of high-voltage switch contact resistance (loop resistance), and is also suitable for other occasions that require large current and micro-resistance measurement.

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 fails, and the fuse is not installed or is fused;

Method of exclusion:

Check and rule out. (100A instrument insurance is not less than 6A, and 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.