(i'm new) How do i synchronize 2 motors a 20hp&15hp motor

Discussion in 'The Projects Forum' started by Mr. Alex, Oct 13, 2014.

  1. Mr. Alex

    Thread Starter New Member

    Oct 13, 2014
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    so we had our envelope machine modified and the tech that did it cant get it right . this machine has to move 1 to 1 every time the motor rotates . so after he tore it down he got new drives and installed new dynamic brakes and now he cant get the motors to start at the same time or stop at the same time ... i'm not much of of a tech . the motors are 480v ac 20hp & 15hp and now he is talking about installing encoders ..... if you need more info just let me know and i will do my best to get you the info
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What are the nature of the motors? I assume 3ph induction motors?
    How/what are they controlled with? simple contactors?
    Induction motors are not good candidates for synchronizing with each other, even with VFD's and encoders.
    Did this machine run OK at one time?
    Max.
     
  3. Mr. Alex

    Thread Starter New Member

    Oct 13, 2014
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    they are controlled by a Dura Pulse AC drive (GS3 20HP AC DRIVE 460VAC 3 PHASE and GS3 15HP AC DRIVE 460VAC 3 PHASE) ... yes the machine would run right but would have problems with the timing not always working right . this envelope machine was built in the early 70s and the parts obsolete . these envelope machines are more updated and only run ONE motor cause of the timimg issues in the past
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Encoders on induction motor/VFD's usually allow close Velocity control, but not really matched position, and it depends on how close the motors have to be synchronized, close synchronization is normally done with one slave servo motor electronically geared off of the other master encoder.
    Using induction motors only, it would make sense for the later M/C's to use a single motor to drive both processes.
    I assume by 'Envelope' machine this is a machine used in the process of punching out and/or folding stacking of mailing type envelopes etc?
    Max.
     
    Last edited: Oct 14, 2014
  5. Mr. Alex

    Thread Starter New Member

    Oct 13, 2014
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    Max ...
    these two motors had synchronisers originaly and it worked when the was a new system , but we bought the upgrade (he recomended) to avoid timimg issues and now this tech cant get it to time 100% ... dont get me wrong ,this tech is sharp and help Sabina get developed ,but i think he needs more answers and not more parts ...
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I would be interested in the method they used, I assume by synchronizers it implied electrical/electronic, not mechanical?
    It is hard to help remotely when the mechanical details of the machine are not known.
    Is there any thing on the web that explains the machine?
    Max.
     
  7. Mr. Alex

    Thread Starter New Member

    Oct 13, 2014
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    not really ...the discription is a F.L. Smithe RA envelope machine .... i'll see if i can upload a pic from our other machine how its set up and see if it makes ant sense
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I recently did work on a F.L. Smithe 3 axis envelope stamping machine, it had a Fagor CNC retrofit.
    Max.
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I saw one Utube video where a RA machine had been rebuilt, and I noticed they used Belco Timing belts on the machine, if this is not original, this may have been the answer to synchronization possibly?
    Max.
     
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