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IndustryArena Forum > MetalWorking Machines > Okuma > Okuma mc-4va alarm 558 B
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  1. #1
    Join Date
    Nov 2016
    Posts
    42

    Okuma mc-4va alarm 558 B

    Hi
    I have get the 558 alarm B on my mill when I input the speed to the machine it doesn't run its spindle then it gets the 558 alarm B please help.

  2. #2
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by shakoori View Post
    Hi
    I have get the 558 alarm B on my mill when I input the speed to the machine it doesn't run its spindle then it gets the 558 alarm B please help.
    any text information with the alarm?

    If the spindle doesn't run it could be many things.

    Tool not clamped
    Operator door not closed and locked
    Tool Changer not in correct position
    Spindle drive fault
    Drive enable fault
    Etc

  3. #3
    Join Date
    Nov 2016
    Posts
    42

    Re: Okuma mc-4va alarm 558 B

    Thanks for the answer
    Before the 558 alarm I get the OC alarm in spindle drive 5 or 6 times in a day so I decided to change the igbts places together after the change motor doesn't start and I get the 558 alarm on NC

  4. #4
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by shakoori View Post
    Thanks for the answer
    Before the 558 alarm I get the OC alarm in spindle drive 5 or 6 times in a day so I decided to change the igbts places together after the change motor doesn't start and I get the 558 alarm on NC
    If the new transistors are good, then the transistor drivers could be faulty, damaged by the bad drive transistors you changed.

    You need to remove the drive and have it repaired.

  5. #5
    Join Date
    Nov 2016
    Posts
    42

    Re: Okuma mc-4va alarm 558 B

    I don't purchased new transistors. I just replaced the transistors place

  6. #6
    Join Date
    Mar 2007
    Posts
    84

    Re: Okuma mc-4va alarm 558 B

    Quote Originally Posted by shakoori View Post
    I don't purchased new transistors. I just replaced the transistors place
    This is incorrect way of repair- base transistor modules should be replaced with new (or used but working) modules. At the same time transistor drivers plus its corresponding power supply side should be checked for correct work. Usually problems with power modules start with power supply faults (bad capacitors, conductive dust and so on). OC alarm 5 to 6 times per day could be a sign that base transistor modules are slowly degrading- they simply become a bit slower and during switching couldnt close as fast as new. In this case they come into linear mode and overheat. I would suggest to replace them together with all electrolythic capacitors on control boards while VFD is still alive. I know it could cost a bit, but it is still cheaper then repairing completely dead VFD.
    Alarm 558B means that spindle gear change is impossible (no gear change confirmation). This could be due to mechanical gear change error, faulty limit switch or shifted limit switch dog, speed range confirmation limit switch fault, bad spindle speed range change solenoid or defective output card or some blown fuse on it. Check these things (I hope You have MC-4VA operation and maintenance manual? There are hydraulic circuit diagrams with LS (limit switch) placement).

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