Fault : ( OI ac ): Instantaneous output over current detected

Discussion in 'Automation & Control' started by DS@Tech, Jul 5, 2019.

  1. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Hello,

    I need some help with a VFD.

    When I power up the unit, the error ( OI.AC ) is displayed, even with the motor and cables disconnected.,

    Can someone please advise

    Thanks
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    18,248
    5,604
    A make and model would help!
    And possibly a link to the manual!
    Max.
     
  3. be80be

    AAC Fanatic!

    Jul 5, 2008
    1,789
    351
    I had 2 do that just this last week
    One was it was too hot where it was installed. And one was the guy I let wire up the motor didn't tape the butt splices up good.
    I just did and new carwash 32 VFD the room where there at hit about 110 f
    The one that shuts down has no cabinet fan.
    The room did have air condition they figured it save money not to have it new air going in this week.

    Your case tho with no motor it should not show error or most don't
    read the manual and reset the VFD
     
  4. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Hello

    VFD: EMERSON
    Model: M200 ( 45/55 Kw ).

    Motor is Ok, and ables where tested and are ok too.
    Both motor and cables are disconnected from the vfd.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    18,248
    5,604
    It would appear you may have a defective IGBT on the output, that error should only show when motor and cables are connected to the 3ph output.
    Max.
     
  6. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Thanks Max.

    I'm going to check the IGBT module.

    Best Regards
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Is there a braking resistor fitted?
    Max.
     
  8. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Hello Max.

    No braking resistor.

    DS
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Then it seems to come back to the power output device(s) shot.
    Max.
     
  10. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Hello Max,

    Can you please give me an opinion related to, what should I check in the equipment.

    regards
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    5,604
    You would have to inspect the IGBT or other power devices for failure, short circuit etc on the output.
    Max.
     
  12. DS@Tech

    Thread Starter New Member

    Jul 5, 2019
    6
    0
    Hello Max,

    Can you help me with this.
    I've read the manual, off this equipment, but I'm having some difficulties on resetting this error, can you please advise.
    this software is not the most intuitive.

    Thanks,
    DS
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
    18,248
    5,604
    As I mentioned, If the output is disconnected, there should not be an OL error, if it does it at switch on without any thing on UVW, then it points to a short in the VFD output, if so you cannot reset it until the defect/fault is resolved.
    Max.
     
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