Failure phenomenon and solution of loop resistance tester

Phenomenon one

The test current of the loop resistance tester is normal, and the highest micro-ohm value 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.

Phenomenon two

Press the "test switch" on the loop resistance tester, the ammeter shows no current, and the highest position of the micro-ohm meter shows "1".

reason

The 100A current loop is not connected properly. The subject switch was not closed.

Method of exclusion

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

Phenomenon Three

The loop resistance tester 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 blown.

Method of exclusion

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