Komori L528 "main motor, main motor fan overload"

Discussion in 'Komori Printing Presses' started by adcellprinter, Jun 21, 2012.

  1. adcellprinter

    adcellprinter Member

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    hi guys, just having a problem with a loud knocking/banging/gear slap sound like its coming from the 5th unit/gripper transfer, then error number 1 (main motor/main motor fan overload). the suggestions in the book are to reset the thermal relays. however none of them are turning off. we "fix" the problem by hitting 6(rst) on the white box(inverter?) inside the main electrical cabinet and then continuing as normal. however we have found that when it happens we have to run the press slower and slower to stop it from happening again. for example we often run the press at about 13800 iph but the other night we could only get up to 12000 before it would start happening .
    any ideas??
    could a guard be the culprit? if it was just slightly activating?
    is it a problem with the inverter? or power supply?
    or even the motor itself?
     
  2. adcellprinter

    adcellprinter Member

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    also i forgot to say, our engineer cant see anything mechanically wrong, and the electrician seems to think inverter. we are just trying to explore all the options because its a very costly fix, $20 000 for a new inverter apparently! anyone with experiences would be great.

    also its an intermittent problem, it seems to happen more often towards the end of the day.
     
  3. presselectronics

    presselectronics Senior Member

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    If you are resetting the inverter, what is the error.? If the problem is electrical (usually sounds more like a rumble or like the motor is coming apart) and is related to the main motor or inverter, before replacing the VF61 inverter, replace the encoder located on the motor. Encoder failures to inverter failures are about 9 to 1. Especially on the 28" press.
     
  4. Yorkshire Gripper

    Yorkshire Gripper Senior Member

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    Sounds like something seizing up around unit 5 transfer when it gets hot and causes the motor to trip/overheat/overload. Must be something significant if it is tripping the motor. When it happens take a few guards off in that area and check for hot spots. Check oil supplies to the main assemblies and gripper shafts for being free. I'd be very wary of running it without finding the root cause of the noises.

    YG
     
  5. John A.

    John A. Senior Member

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    It sounds to me like presselectroncs has hit the nail on the head the encoder is failing. I had this same problem once and went to replace the encoder and found it was simply loose. Tightened the allens with lock tight and returned the encoder to Komori. Could be why your problem is intermittent.

    John
     
  6. klecman

    klecman Senior Member

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    When the problem starts, what is the current reading on the meter located on the main electrical box?
    After warming up, is the press difficult to crank from the manual handle?
     
  7. adcellprinter

    adcellprinter Member

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    Sorry for the lateness of my reply but I had a few days off and then we haven't had the problem for a couple of days. The main reason that it hasn't happened is that we've been running the press a fair bit slower than normal around 11000 iph, while we try and line up a new inverter and encoder.

    The press isn't any harder to crank over after the problem starts. I haven't been able to watch the meter while the problem happens but in normal operation today it's sitting on 40-50. But I'm sure when I've looked in the past it's been more like 50-60.

    The error on the inverter is "oU". I don't know what that means.

    I have taken off the guards and felt for hotspots and inspected the gears by eye but can't find anything that would be of concern. I've been pumping grease into all of the grease points I can find. I've also turned up the auto lube on the delivery chain as it was looking dry and I thought it might be binding as it was turning around near the 5th cylinder.

    Anyway thats where I'm at. Has anyone got any more ideas or some info on the inverter error?
     
  8. adcellprinter

    adcellprinter Member

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    Also it happened again tonight at 11000 iph and then at 10700 iph after I turned it down
     
  9. John A.

    John A. Senior Member

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    Have you taken the guard off the main motor and checked the encoder?
     
  10. adcellprinter

    adcellprinter Member

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    Actually no I haven't, I'll have a look tomorrow. Although I don't really know what I'm looking at, what does it look like and where on the motor do I find it?
     
  11. klecman

    klecman Senior Member

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    According to the manual, Error oU indicates "Excessive DC Voltage" and the recommended solution is to "Increase deceleration time". Often the error codes merely mean something wrong with the system. The problem could be caused by anything from a faulty encoder to a faulty component in the VF-61. The best approach is to have it checked by a specialist familiar with the VF-61.
     
  12. John A.

    John A. Senior Member

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    It is a disk shaped gizmo that fits onto the end of the motor drive shaft. There should be some allen screws holding it in place. It should be on the operator side of the press, remove the first motor cover and you will know it when you see it.
     
  13. Printermike

    Printermike Member

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    uU error

    Have a komori mech in. Getting rumbling from motor on startup.
    Was told it was the optical encoder. Tech from komori now says its the main drive. 10k for drive. Any ideas?
     
  14. presselectronics

    presselectronics Senior Member

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    Was the encoder replaced? They are not easy to test so I always recommend replacement for any similar motor problems.
     
  15. Printermike

    Printermike Member

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    Encoder

    Encoder replaced same problem as before. Komori shipping in a new drive.
     
  16. Printermike

    Printermike Member

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    Price for drive is 10k with a 20% rebate with old drive returned.
    Hoping this solves the problem. 10k was a kick in the shorts in this
    Economy.

    Any other ideas?
     
  17. klecman

    klecman Senior Member

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    I once got one working by using the "Autotune" function. Have the technician get in touch with Tony in Chicago. I found the autotune instructions in the manual that came with the new drive. You have to remove the drive belt but it's worth a try.

    I found the autotune instructions on page 10 of the VF61 instruction manual under the name "Automatic measuring operation".
     
  18. presselectronics

    presselectronics Senior Member

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    Excessive DC voltage can be caused by a bad inverter. Looks like you have that covered. The other causes I have seen are high supply voltage, the encoder, motor belts, the main motor itself and mechanical problems causing the load to vary excessively.

    Basically the inverter takes AC and converts to DC and then chops that up and produces the voltage/frequency to the motor. If the motor decelerates too quicky, the voltage produced by the motor is fed back into the DC bus and if enough is fed back, you get a DC bus overvoltage.
     
  19. Printermike

    Printermike Member

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    Komori

    Thanks for the info. Tony in Chicago told us it was the optical incoder.
    Have Dan from komori coming back in the morning. He told me about the auto tune but said our model doesn't use the auto tune. We have a "28 5 color.

    I"ll talk to Dan tomorrow and show him your comments. Appreciate the help guys. Keeping my fingers crosses it isn't the drive. I'd be great not to have a huge parts bill.

    Mike
     

  20. Printermike

    Printermike Member

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    Error we are seeing on drive is uU. Which the manual says is low voltage.
    Dan checked the taps on the transformer. An also bumped the voltage up slightly.
     
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