Fanuc Rj3 IPMAL alarm on J4

    Hello there

    I am having a long term trouble with J4 issuing IPMAL error. The strange part is whenever i restart the machine it runs for few hours and errors out again. any suggestion please ?

    Trouble shooting done so far: Meggered the motor cable results were >200Mohm

    : Replace the IGBT unit on J4


    :smiling_face::smiling_face:

    When you get the alarm is the robot in a very similar position on one or more of the axis? If it does happen in a similar position each time wait until you get the alarm and check your resistance again to see if you then have a short somewhere. My guess would be that the cable is being pinched somewhere but only when the robot moves a particular way.

    "I could tell that my parents hated me. My bath toys were a toaster and a radio."

    You could be right as it only happens when running a particular program. but so far the operators have only been running that one program and havent tried any others. I was reading the other post from skooter which alive 15 recommended, it could be overheating aswell. "maybe"

    R-J3 6-axis servo amps can be frustrating. To give your troubleshooting a direction, try swapping the entire amplifier with a known good one if possible. While replacing the J4 IPM is a good start, it doesn't cover the other servo amp circuitry involved with the IPM operation.


    It doesn't seem like it should overheat unless the servo fans are not working in a hot environment. I would assume the heat sink, fans, and cabinet vents were cleaned when the servo amp was removed to replace the IPM.

    Hi

    I was trying to replace the IPM module but realized that the spare one is 75A rated. So i cleaned the one which was giving issue and put some new paste. Hooked back up and its running now. So my question is:

    1.. If it was the IPM module it should have failed straigjt away right?

    2.. Can i replace the 50A with 75A IPM module?

    3..Before taking it out I tried to restart the machine few time by completely shutting off power but it gave the IPMAL error straight away.

    4.. Checked the cable which seems to be fine.


    :thinking_face::thinking_face:


    Thanks

    1.. No. There is a lot of electronics inside that may degrade/change enough over time to cause issues under normal conditions.

    2.. The amp is designed for specific Fuji Electric IPM modules. Fanuc has specific part numbers for these. I've never replaced one with anything but the original part number. Installing a larger IPM may not go well.

    3.. Again, there is is other circuitry that process the IPM alarm output that may be the issue. If you repair them for a living, intermittent IPM alarms are tough to replicate. Usually replace the IPM and some associated circuitry just for insurance against warranty issue.

    4.. Cable issues can be tough because they may only break down in certain position only under a high voltage position. When the consistent IPM alarm was on, then was the time to check the motor cable and motor. ALWAYS disconnect the amplifier motor connection before using a high voltage insulation tester (sometimes called a megger).


    Try to narrow down the IPM by swapping it with another 50A located at J5 or J6.

    Ensure you use only enough thermal grease to fill gaps in the metal-to-metal contact. If the thermal grease is too thick, it limits thermal transfer.

    Don't over- or under-tighten the IPM screws. Don't remember the torque values off hand.

    Hi Skooter

    thanks for your reply. really appreciate.

    1..So whatever i have done will sure fail sometime soon.

    2..Also the IPM module which i replace was not original. It was a Chinese one maybe thats why it is failing?

    3.. I will try and replace it with J5. Just to see if the error follows or if there is some other related issue.

    4..Which thermal grease is ideal for that ? Can i use the computer heat sink one?


    Thanks :smiling_face:

    1.. Not necessarily soon. Some electronic components degrade and/or change over time such as some types of capacitors, opto-couplers (opto-isolators).

    2.. I've only seen the original Fuji Electric used.

    3.. Good

    4.. Computer heat sink compound/grease/paste should be fine. Make sure to clean both surfaces and use a very thin, very even coating to get maximum heat transfer.

    The tag on the part shown has the original A50L-0001-0304 Fanuc part number and the FE part number matches as well. It also shows it was made in Japan during Nov, 2006 (6Nxx).


    I don't have experience with this company so I don't know if it will work or is original. The price is much lower than what was when it was available in the past thru Fuji Electric U.S. distribution.

    yes and he also said that they buy it from fuji japan and sell them as wholesalers. I think I will just buy it and see as they are cheap anyway. Also we ran the machine yesterday for almost 2 hours and it was fine. As you said the electronics degrade after a while so maybe expecting sooner or later.

    I will update you.

    Thank a lot for your help.

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