Motor temperature A4

  • Hello,

    We are recently facing a malfunction in our robot KUKA KR 360L280 with KRC2 controller. After working for 5 hours approximately, the robot suddenly stopped stating 'motor temperature A4'.

    We monitored the variable TempA4 it was fluctuating between 390 and 410 Kelvin. We sensed motor 4 with our hands, it was like 290 Kelvin because if it was actually 390 Kelvin, we wouldn't be able to touch the motor.

    Also, we tried to switch the cables between A4 and A5 then played a program for a full day...nothing happened and all the motors temperatures were normal.

    My question is, what do you think can cause such problem? can the temp sensor in the motor be replaced? or do you prefer to change the cable? or drive?

    Thanks in advance,

  • SkyeFire

    Approved the thread.
  • when temperature sensor is not connected (or has bad connection), you get message like that. potential places of failure could be motor (sensor), motor cable (inside robot arm), RDC.

    you can open RDC, unplug sensor cable for A4, then check with multimeter resistance of the connector circuits. there are 4 such circuits:

    1. temperature sensor (about 600 Ohm at room temperature, about 1k is max when really hot.)

    2. resolver excitation (low, resistance, few ohms)

    3. resolver SIN output (low, some 10-15 ohm)

    4. resolver COS output (like SIN output)

    if the wiring and sensor are ok, it would be the RDC that is a problem.

    in that case one can move A4 connector to one of spare channels like (7 or 8 ) and edit MADA.

    for test (or if you do not care about motor temperature) you can connect 620 or 680 ohm resistor to RDC to fake the temperature sensor.

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

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