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

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

    Solution: Check and eliminate the issue. (For 100A instruments, if the fuse is not less than 6A and blows again, contact the manufacturer. 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 displays “1" in the highest digit.

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

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

    3. Phenomenon: The test current is normal, but the micro-ohm value displays “1" in the highest digit.

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

    Solution: 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: The output current is tens of times less than 100A.

    Cause: The power supply voltage is too low, the power cord has high internal resistance or poor contact, or the voltage drop is too large when there is DC output, failing to reach 190V. The C1 and C2 terminals are loose. The tested loop and test lead clamps have poor contact.

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

    5. Phenomenon: The test current is normal, but the micro-ohm value displays abnormally and is not repeatable.

    Cause: The voltage signal loop has poor contact, intermittently connecting and disconnecting. The tested resistance itself has poor contact, causing resistance value changes.

    Solution: Ensure good and reliable contact. Check and eliminate the issue.

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

    Cause: The voltage clamps are misplaced, with positive and negative reversed.

    Solution: Correct it; it should be: P1+, P2.

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

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

    Solution: 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