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I changed 3 times AVR I need the root cause of the problem

Discussion in 'Generators/Gensets' started by alaa, Jul 8, 2017.

  1. alaa

    alaa Member

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    Hi,
    I have changed 3 AVR on Perkins Generator 2306C-E14 (FGB061018U4412K) after explosion or burnt
    each one 2 to 3 weeks ....I need the root cause of the problem ....
    Thanks Eng's in advance...
     
  2. Birken Vogt

    Birken Vogt Charter Member

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    That is the model of the engine but it does not tell anything about the generator.

    What kind of generator is this on?
     
  3. alaa

    alaa Member

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    Thanks for reply
    the generator LS Leroy Somer
     
  4. Birken Vogt

    Birken Vogt Charter Member

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    Leroy Somer Model number?

     
  5. alaa

    alaa Member

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    Leroy Somer Model number RPES2 by FG wilson
     
  6. Birken Vogt

    Birken Vogt Charter Member

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    That looks like the FG wilson number, not the number of the Leroy Somer alternator...and we have nothing like that FG Wilson unit over here near as I can tell.

    Have you tried discussing it with FG Wilson?

    Otherwise try and find the Leroy Somer model on the alternator itself.
     
  7. spark

    spark Member

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    My experience this happens when the exciter field becomes shorted. The only load of the AVR is the exciter field. I have had numerous times with failures and the only cure was an exciter field (exciter stator) replacement.
     
  8. alaa

    alaa Member

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    Thanks gents,
    I attached to the name plate of engine and alternator ... about the resistance of exciter stator was 11 Ohm
    now it's running at 50% of load with direct connection of 12VDC for more than 10 day's with out AVR.
    Still with out any solution.

    IMG-20170710-WA0000-1.jpg IMG-20170710-WA0001-1.jpg
     
  9. Birken Vogt

    Birken Vogt Charter Member

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    That exciter resistance sounds a little bit low. I can't find what the specification is supposed to be on this model, though. Also, did you check exciter stator for grounds?
     
  10. spark

    spark Member

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    Look under leroy-somer.comdocumentation-pdf4455_en.pdf for that type it shows 12.5 ohms exciter field resistance
     
  11. Birken Vogt

    Birken Vogt Charter Member

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    Assuming the field is not grounded or intermittently shorted, I would next try an aftermarket voltage regulator and see if it behaves any differently.
     
  12. alaa

    alaa Member

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    Thanks gents
    Exciter not grounded I'm not sure the value ... but let me guess that was to ground 14 K ohm or more....
    Is there any relation with back power to the neutral cable...
     
  13. Birken Vogt

    Birken Vogt Charter Member

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    http://www.leroy-somer.com/documentation_pdf/4455_en.pdf

    Another thought, it might be a rotating diode failed. This would cause the AVR to work harder for the same output.

    If I recall, it is a lot of work but you might be able to reach in and disconnect the individual terminals from the rotating rectifier and test the diodes individually on this model.
     
  14. alaa

    alaa Member

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    I did not test the diodes ... but it will fail and show up 0 Volt from the beginning when I start the genset even with the direct 12 DCv,like it is now working by 12 DCv supply....
     
  15. Birken Vogt

    Birken Vogt Charter Member

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    So you are saying sometimes it will not work even with 12 VDC applied? But usually it does?
     
  16. alaa

    alaa Member

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    No ... bro ... Now the generator working with 12Vdc applied with out AVR and and working fine with load around 40% from rated Kw ...I wish it will not damage the alternator ....
    I will not give up