UPS Fault Analysis and Maintenance Methods

I. First, inspect the UPS insulation.

　　In the EPS2000, the DC ground of the module section is floating and electrically isolated from the frame; therefore, insulation between the module and the frame must be taken into account, as a potential difference of several tens of volts typically exists between them.

　　II. Secondly, you must also read the fault alarm information displayed on the UPS monitor.

　　III. Zero-Volt Voltage Reference Point

　　1. PCB ALIP FAULT (Power Board Fault)

　　Inspection and Analysis:

　　1) Check whether the input voltage of the ALIP is normal;

　　2) Check the ALIP board output for short circuits. The inrush current at the moment the PC board is powered on can cause a short circuit at the ALIP board output, triggering the ALIP board’s protection circuit or even damaging the ALIP board.

　　2. EMERGENCY POWER OFF – Emergency Shutdown

　　Possible causes:

　　1) On the FLIP board, verify that the jumper wire between XR9 pins 1 and 2 is properly connected.

　　2) On the FLIP board and AQCP, track and observe whether the “emergency power off” signal is abnormal.

　　3) If the small transformer in the FILP unit is orange-yellow and its model is SIRIO, short-circuit resistor R108 (10 kΩ) on the AQCP board, or replace the AQCP board.

　　3. PCB AQCP/AQOP/CANP/CHAP ODUP/AFIP/DISPFAULT

　　First cause: Replace the display PC board. If the fault persists, inspect the connections and then replace the CANP board.

　　Second reason: If the self-diagnostic system indicates faults on several boards, replace the CANP board.

　　4. COFP FAULT

　　Possible causes:

　　1) When starting the UPS, as soon as switch Q1 is closed, the UPS powers all PC boards and analyzes the various responses sent by each board. To obtain the responses from the remote control, the remote-control power supply must be turned on before the UPS; that is, when starting the UPS, switch Q4S must be closed first, followed by switch Q1. If both the UPS and the remote control are already powered up, a diagnostic function program should be used to perform a reset.

　　2) Check whether the remote control’s input power supply (220 V) is normal, and whether the FUSEs FU23 and FU22 (2 A) on the FILP board have blown.

　　3) Has resistor R35 on the AFIP board of the remote control been removed? Normally, it should not be there.

　　4) If the remote control is not connected but the above phenomenon still occurs, then:

　　a) Verify that the UPS internal program presets are configured correctly;

　　b) Inspect the connections between the PC boards;

　　c) Replace the CANP board.

　　5. Battery Failure

　　1) First cause: a very strong hydrogen odor and visible oxidation of copper or brass components; the batteries swell significantly and press against one another. To determine the root cause, we must first ascertain whether these symptoms occurred over a relatively short period (8–10 hours). If so, the likely cause is a control-system malfunction, possibly stemming from the PC board’s CHAP or AQCP module. In this case, perform a charger-startup test with QF1 open and verify the actual DC voltage.

　　2) Second reason: battery swelling. If the inverter has been shut down for an extended period, the temperature may have dropped; in this case, check the number of swollen batteries and their corresponding float charging voltages, and identify any batteries that are short-circuited.

　　3) Add an inductor to the DC circuit to reduce the AC component;

　　4) Inspect the battery terminals for tightness;

　　5) Check the information sampled and returned by the shunt;

　　6) Check the charger’s operating condition;

　　7) If a fault occurs or the display shows “MAX BATT FAULT,” the issue may be with the AQCP, CANP, or CHAP.

　　6. BATTERY 0V

　　1) Check the wiring of the shunt sampler (the shunt value between pin 1 and pin 2 of XF1324 is approximately);

　　2) Check the battery status (e.g., discharge);

　　3) Compare the actual voltage value with the displayed value, identify the cause based on the observed error, and replace the PC board AQCP or CANP.

　　4) Inspect the static switch (S.S);

　　5) If fuse FU6 blows, battery current monitoring will be halted.

　　7. M2 RC FU BLOWN

8. FU1 RU2 RUSE BLOWN

　　Reason:

　　1) AILP board failure;

　　2) Instantaneous high-voltage surges in the external power grid;

　　9. FU3 BLOWN

　　Reason:

　　1) AQCP board failure;

　　2) C6, C7, C8, leakage (719162P-FILP)

　　3) C3, C6, C9, leakage current (6716730-FILP)

　　10. FU4 BLOWN

　　1) Check the insulation resistance between the DC ground and the cabinet;

　　2) Check the capacitors on the FILP board for leakage or breakdown.

　　11. FU6 FU9 BLOWN

　　Reason:

　　1) ALIP board failure;

　　2) K3N coil short circuit

　　12. INPUT FUSE BLOWN (Input Fuse)

　　1) Check whether the charger’s thyristor is in good condition;

　　2) Check for DC short circuits;

　　3) Inspect the insulation of the battery’s positive and negative plates with respect to ground;

　　4) Replace the CHAP board, then the charger module (a faulty CHAP board can damage the new charger).

　　13. INV RUSE BLOWN (Output fuse blown)

　　These fuses typically blow when the load is switched to the inverter, due to excessive circulating current in the output transformer.

　　To identify the cause, the following examinations can be performed:

　　1) Open switch Q4S, forcibly start the inverter using the forced-start method, and forcibly switch to the load;

　　2) Check whether the static switch thyristor is in good condition and whether the K3N coil is functioning properly;

　　If the LEDs on the panel turn off during switching, it could indicate a failure of the static switch’s thyristor or a phase-sequence and phase fault in the inverter.

　　3) Inspect the power supply’s input RC protection circuit;

　　4) Verify that the power supply neutral conductor complies with standards;

　　5) Verify that the grounding of the inverter cabinet and the battery cabinet (rack) is adequate;

　　6) Check for short circuits in the load.

　　14. LEGALIZATION

　　Main reason:

　　① Inverter failure (transistor or control board);

　　②ODUP board failure

　　15. INV LEGX POWER SUPPLY FAULT

　　16. INV START-UP FAILURE

　　17. INV CURRENT LIMIT

　　18. INTERFERENCE FAULT

　　19. S.SOR K3N RESPONSE FAULT

　　1) Static switch failure

　　2) K3N failure

　　3) Power supply issue for the K3N coil

　　20. WRONG M1 PHSEQ

　　1) If the fault occurs during the first power-up, check whether the mains power supply is connected correctly.

　　2) If a fault occurs during machine operation, causing the charger to shut down and display the “WRONG M1 PHSEQ” message;

　　21. OUTPUT OVERLOAD

　　1) First, determine whether the load is truly overloaded;

　　2) Start the loads one by one to identify which load has excessive inrush current or mechanical stall.

　　22. When all the lights on the panel are illuminated, it usually indicates a fault with the AFIP board.

　　23. UPS FAN FAIL URE (FPS Fan Failure)

　　1) Inspect the fan wiring and plugs for looseness, and check for any abnormal noises.

　　Check whether fuses FU13, FU14, FU15, and FU16 (2 A) on the FILP board are functioning properly.

　　2) Check whether the voltage between pins 10 and 11 of the AQOP board XM603 is 0 V. This voltage can be measured at resistor R37 on the AQOP board; if UR37 = 0 V, the circuit is functioning normally.

　　3) If the above measurements are correct but the display still shows “INV FAN FAIL URE,” replace the AQOP board.

　　4) If the issue persists after replacing the AQOP board, the fault lies with TQ1 on the FILP board.

　　24. OVERHEAT AND SWITCHING MICROCONTACT FAULTS

　　1) Identify the source and cause of overheating and take measures to eliminate it;

　　2) Check whether the auxiliary switch is functioning properly;

　　3) Check whether the 24 V voltage signal is normal;

　　4) A self-diagnostic test program can be developed to isolate and verify the identified fault locations.

　　5) The fault may also stem from the 24 V power supply. Check whether the 24 V output voltage on the AILP board is normal; the board provides two 24 V outputs, one at XM102 and the other at XM101.

　　25. No 24V power supply

　　26. No +12V voltage

　　27. No -12V voltage

　　28. No +16V voltage

　　29. No -16V voltage