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IndustryArena Forum > MetalWorking Machines > Fadal > X-axis motor replaced -> problems
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  1. #1
    Join Date
    Mar 2007
    Posts
    23

    X-axis motor replaced -> problems

    Hi!

    We have 1997 VMC-15XT with 88HS. Earlier today X-axis motor overheated smoked and failed. We repladed motor with brand new one but there seems to be problem. When machine is powered there is small noise and we found out that x-axis is drifting back and forth constantly very little amount. Also x-axis "amplifier balancing" reading is jumping from +3 to -12 (Y and Z are steady 0/1). I tried to swap X/Y amp cards but problem is still on x-axis.

    Do we have faulty motor?

  2. #2
    Join Date
    Mar 2003
    Posts
    900
    It sounds like either the encoder has a problem or the servo gain needs adjusting. When ever a motor or amplifier is replaced is a MUST to re-do the servo loop gain.

    Neal

  3. #3
    Join Date
    Mar 2007
    Posts
    23
    Quote Originally Posted by Neal View Post
    It sounds like either the encoder has a problem or the servo gain needs adjusting. When ever a motor or amplifier is replaced is a MUST to re-do the servo loop gain.

    Neal
    How does it happen? We have replaced motors in our fadals many times with just plug'nplay. But not this one

  4. #4
    Join Date
    Mar 2003
    Posts
    900
    Each motor and each amplifier has their own distinct characteristics. The fact that you change one or the other without retuning only means that they were very close to the replaced item. Without the retuning you were not getting maximum performance from the system.

    Neal

  5. #5
    Join Date
    Feb 2005
    Posts
    376
    The X axis, the one with the flex conduit floating around in the machine? The one that cracks occasionally, the one that is always moving, the one that is constantly coated in coolant and chips. I would give that very serious consideration.

    A motor should not just start smoking, and I would make sure I knew exactly why it was smoking before throwing another one in, especially if the wires going to it are always moving.

  6. #6
    Join Date
    Mar 2007
    Posts
    23
    We had that cable replaced ½ year ago. I spoke with fadal service and they told to adjust loop gain / balance from amp card.

    DC Amplifier
    Adjustment
    1) Enter the following program:
    a. X-4. Y-4. Z-4. G1 F150. M49,M91.
    b. X4.Y4.Z4.
    c. M99P1
    2) Press Auto, to start the program running.


    Easy.


    3) At the amplifier to be adjusted, use a small screwdriver and turn the SIG2
    potentiometer until the monitor’s display of the appropriate axis reads the
    following error: 595 - inch ballscrew / 302 - metric ballscrew.


    We have inch ballscrews. AMP card didnt have SIG2 pot but there was SIG pot. It took amazingly many turns to reach numbers around 600


    4) Press the SLIDE HOLD button on the keypad and adjust the balance of the
    amplifier to read between 0 - 1.


    Here is the problem, balance reading won't stay still to be adjusted, it bounces around from -6 to 14 constantly.


    5) Press the START button on the keypad and the program will start again.
    Verify that the following error is still 595 or 302.


    Wont get stable reading here as well, reading is bouncing 550-650 when X is moving

  7. #7
    Join Date
    Mar 2007
    Posts
    23
    [ame="http://www.youtube.com/watch?v=sgaRbr-MlQM"]YouTube - Fadal VMC-15XT X-axis problem[/ame]

    Crappy quality video about our problem. Suggestions? Tried again to swap servo amps between X and Y but problem stats on X-axis. Servo amp adjustments wont help.

  8. #8
    Join Date
    Jan 2005
    Posts
    53
    You need to check and/or replace your resolver pins at the motor. Chances are there is corrosion on the pins.

  9. #9
    Join Date
    Aug 2008
    Posts
    3
    did you get the problem fixed

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