DC link voltage too low warning

  • Hello to everyone. I have 2 ABB Robots in my hand.

    MODEL IRB 6700


    Both Robots are fed on the same power line.

    Suddenly, both robots started giving DC link voltage too low warning.

    Error Code 34401

    When I measure the energy coming to the robots, the problem does not appear.

    I turned off the main power and checked the Cables by hand, there was no slack.

    Robots have different failure times, so I don't think it's a sudden energy surge.

    And I don't think it's a cable problem either. Because this problem started suddenly, both robots could not have their cables loose at the same time.

    The description of the fault is written like this in the technical manual.

    34401, DC link voltage too low warning


    In drive module arg, the drive unit at unit position arg has a DC

    link voltage that is close to minimum limit.


    Operation will be possible but the system is close to a stopping


    Probable causes

    The incoming mains voltage to the rectifier unit is out of


    Recommended actions

    1) Check for other hardware eventlog messages regarding

    mains voltage problem.

    2) Check incoming mains voltage. Change the mains tolerance

    min so that the mains voltage is inside the specified interval.

    3) Check that the correct voltage is selected with jumpers on

    the transformer (optional).

    4) Check all internal 3-phase components (main switch, mains

    filter, fuse, contactors) and cabling in the drive module.

    I tried all the possibilities but couldn't fix the problem.

    I am sharing a photo of the fault below.

  • What are your suggestions for a solution?

    If the main drive is out of order, can I replace it with the spare part I have?

    What should I pay attention to when changing?

    There is a warning on the main drive.

    "Before replacing main drive system, remove any temp sensors adjacent to the heat sink."

    What are the sensors listed here?

    Since we have very intensive machines, I have no chance to make mistakes, what are the risks.

    Could software problems occur?

    Could there be a calibration problem in axes?

    The labels of the spare parts are like this.

    Is it a problem if I replace it?

  • Is the problem intermittent or constant?

    Are the robots moving when this happens?

    This error can occur if there is a drop in one or more of the incoming 3-phase voltages. Since it happens with both robots on the same line, I would monitor that. If the robots are moving when this happens, their energy usage when the voltage drop occurs may be different enough to only fault one robot.

  • Take a good look at the capacitors on the power supply. if they show any signs of leaking replace them and have the 6-pac refurbished. You may have to do the drives too.

    Also check the contactors K43 and K42 (I believe) If they are older ones, it may be good to replace them and the external contacts. They control the incoming power

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