The loop resistance tester is connected to 220V AC power supply, the fan does not run, and when pressing the "test switch", the ammeter and micro-ohmmeter show no display.

    Cause: 220V AC power supply is not connected, fuse is not installed or blown.

    Troubleshooting: Check and eliminate. (For 100A instrument, fuse not less than 6A; if it blows again, contact the factory. Never connect to DC or 380V AC power supply)

    2. Phenomenon: When pressing the "test switch", the ammeter shows no current, and the micro-ohmmeter's most significant digit displays "1".

    Cause: The 100A current loop is not connected properly. The switch under test is not closed.

    Troubleshooting: Check the test leads, reconnect, re-clamp. Close the switch.

    3. Phenomenon: Test current is normal, but the micro-ohm value's most significant digit displays "1".

    Cause: Incorrect voltage clamp position. The resistance value of the tested loop exceeds 2000μΩ. The voltage signal wire is broken or not connected.

    Troubleshooting: Handle the voltage signal loop, clamp correctly and securely. When out of range: use a multimeter to measure the voltage between P1 and P2; resistance = voltage / current.

    4. Phenomenon: Output current is several tens of amperes, less than 100A.

    Cause: Power supply voltage is too low, power cord has high internal resistance or poor contact, voltage drop is too large when there is DC output, not reaching 190V. C1, C2 terminals are loose. Poor contact in the tested loop and test lead clamps.

    Troubleshooting: Use a qualified power supply, avoid using too long or too thin power cords, handle the tested loop to eliminate poor contact. When tightening C1, C2, P1, P2 terminals, apply appropriate force. (Test current above 30A is reliable)

    5. Phenomenon: Test current is normal, but the micro-ohm value display is abnormal and not repeatable.

    Cause: Poor contact in the voltage signal loop, intermittent connection. The tested resistor itself has poor contact, causing resistance value changes.

    Troubleshooting: Ensure good and reliable contact. Check and eliminate.

    6. Phenomenon: Test current is normal, but the micro-ohmmeter displays a negative value.

    Cause: Voltage clamps are misplaced, positive and negative reversed.

    Troubleshooting: Correct it; it should be: P1+, P2-.

    7. Phenomenon: During calibration testing, sometimes the displayed value fluctuates greatly.

    Cause: During calibration testing, the test leads are coiled like an inductor and not spread out.

    Troubleshooting: Spread out the test leads to reduce their inductance and mutual inductance.

Article link: Chem17.com http://www.chem17.com/company_news/detail/1042843.html