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Regulator/Rectifier

in General Tech Discussion 7 years ago

  • Re: Regulator/Rectifier

    by » 7 years ago

    If you want to fix a problem, you objectively identify the causes and deal with them.

    The above links are not relevant to the the failures of this voltage regulator. I'm disappointed that a Rotax instructor would claim “too little draw” can kill the VR. This shows a complete misunderstanding of how this regulator works.

    I've examined dozens of regulator failures from several airframe models, all failed from the same causes…and it's not the airframe manufacturer at fault. This is typical



    Rotax, Ducati, if you are listening...The Rotax 965-349 Ducati 362001 rectifier regulator is not a lost cause, but you need to deal with the following design and manufacturing deficiencies if you want to put this behind you;

    1) Eliminate the manufacturing induced lead stress on the power components.
    2) The potting compound is too soft, and it's unstable over the rated operating temperature of the regulator. (95 Shore A to 30 Shore A)
    3) Operating stresses (vibration) acting on the pre-stressed leads (item 1), in a potting compound that softens with temperature (item 2), over time results in PCB solder joint separation failures.
    4) PCB connections that were never soldered indicate a poor (or nonexistent) inspection/QC process.
    5) There is insufficient clearance between an un-fused, high current carrying PCB trace and the rectifier’s grounded metal case. The design relies on the insulating value of the PCB's solder mask layer.
    6) Poor connector/plug/tab length design. The design of this 22 amp connection only allows about 80% of mating capacity between the connector’s male tab and female AMP fast-on.
    7) The material for the male tab is 7.5mm thick, this equals .0295", the AMP faston is designed for an .032" tab thickness. The design falls 8% below optimum thickness.

    Mike
    Thank you said by: David HEAL, RotaxOwner Admin
      
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  • Re: Regulator/Rectifier

    by » 7 years ago

    The huge majority of owners don't have issues, but there are commonalities for many of the failures.
    As in any electrical or mechanical part there will always be a small percentage that fail just because they are man made. Even bow / arrows and clubs broke in the Ancient times.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: Regulator/Rectifier

    by » 7 years ago

    Disagreed.
    The failure rate is unexceptable and the blame clearly lays with the manufacturing and design deficiencies referenced. As I explained, all these issues are fixable, but the first step is accept we have a problem Clearly we disagree on that, To blame the airframe manufacture for failed solder joints in a potted device is insulting....And to repeatedly sell this deficient device to users who are married to Rotax because of S-SLSA compliance regulations is unconscionable.

    You can be part of the solution or part of the problem, your choice.
    Thank you said by: David HEAL
      
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  • Re: Regulator/Rectifier

    by » 7 years ago

    In rounded numbers; 50K engines and something like 5 million run hours Rotax has a fairly good track record and the 912 has been around since approximately 1990.
    Many of the malfunctions have come from the users for several different reasons and probably some not.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: Regulator/Rectifier

    by » 7 years ago

    Not relevant to the discussion. My main issues are with the regulator and the identified weakness.

    I have nothing against Rotax, it's not personal. I have no agenda, there is nothing in this for me. My goal is to improve the product.
    Thank you said by: David HEAL
      
    Report
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