Common failure causes and countermeasures of UPS power supply

by:Power Kingdom     2021-06-22

UPS is an uninterruptible power supply. It can not only provide electricity, but also protect the voltage stability, which plays a very important role in our daily life with electricity.

1. When the mains power is available, the UPS will show a mains power failure alarm.

  Possible cause of failure:

  1) Mains input circuit breaker tripped.

   2) The input AC line is in poor contact.

  3) The mains input voltage is too high, too low or the frequency is abnormal.

  4) The UPS input MCB or switch is damaged or the fuse is blown.

  5) The mains detection circuit inside the UPS is faulty.

  Processing method:

  1) Check the input MCB.

   2) Check the input line.

  3) If the utility power is abnormal, do not deal with it or start the generator to supply power.

  4) Replace the damaged MCB, switch or fuse.

  5) Check the UPS mains detection circuit.

  2. When the utility power is normal, the UPS output is normal; after the utility power is cut off, the load is also cut off.

  Possible cause of failure:

   1) Because the mains is often low voltage, the battery is under voltage.

  2) The UPS charger is damaged and the battery cannot be charged.

  3) The battery is aging and damaged.

  4) Load overload, UPS bypass output.

  5) The load is not connected to the UPS output.

  6) The battery pack of the long back-up model is not connected or has poor contact.

  7) The UPS inverter does not start, and the load is supplied by the mains bypass.

  8) The inverter is damaged and the UPS bypasses the output.

  Processing method:

  1) Add a voltage regulator to the UPS input.

   2) Check the charger.

  3) Replace the battery.

  4) Reduce the load.

  5) Connect the load to the output of the UPS.

  6) Check whether the battery pack is correctly connected.

  7) Start the inverter to supply power to the load (open the panel control switch).

  8) Check the inverter.

  3. The UPS cannot start.

  Possible cause of failure:

  1) The battery has been left unused for a long time, and the voltage is low.

  2) The input AC and DC power cords are not connected properly.

  3) The UPS internal startup circuit is faulty.

  4) UPS internal power circuit failure or power supply short circuit.

  5) The internal power components of the UPS are damaged.

  How to deal with:

  1) Fully charge the battery.

   2) Check whether the input AC and DC wires are in good contact.

  3) Check the UPS startup circuit.

  4) Check the UPS power circuit.

  5) Check whether the internal rectifier, boost, inverter and other parts of the UPS are damaged.

  4. When UPS is in normal use, a long buzzer alarm occurs suddenly.

  Possible cause of failure:

  1) The user starts with a large load or a large impact load.

  2) The output terminal is suddenly short-circuited.

  3) The internal inverter circuit of the UPS is faulty.

  4) UPS protection and detection circuit malfunction.

  Processing method:

  1) Increase the power capacity of the UPS.

   2) Check if the output of the UPS is short-circuited.

  3) Check the UPS inverter.

  4) Check the internal control circuit of the UPS.

   5. The UPS works normally but the load equipment is abnormal.

  Possible cause of failure:

  1) The UPS output zero-ground voltage is too high.

   2) The UPS ground wire and the load equipment ground wire are not connected at the same point.

  3) The load equipment is subject to abnormal interference.

   Treatment method:

   1) Check the UPS grounding, if necessary, connect one between the zero and ground of the UPS output terminal 1-3KΩ resistance.

   2) Connect the UPS ground and load ground to the same point.

  3) Restart the load equipment

  Know yourself and the enemy before you can fight a hundred battles. In the face of unexpected UPS failures, understanding the causes and mastering the countermeasures can ensure the orderly progress of power work.

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