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Phantom 1 MTBF

Discussion in 'Phantom 1 Discussion' started by gianni_BT, Mar 13, 2016.

  1. gianni_BT

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    Hi.
    Does anybody know if there are DJI official( or not official) data about the Phantom 1 2 and 3 MTBF(mean time between failures or mean time before failure)?
    In other words, how many hours can we fly with a negligible possibility that a motor can fail and when is suggested to replace them?
     
  2. Air Ontario

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    I have not seen any public documentation. I suppose one could look at component types(small electric motors) and find some general data or loosely use standard MTBF/MTBR/Life expectancy charts or each component.

    It would be interesting especially as a complete operating unit
    (bird/software/firmware/RC) and look at real world reliability.
     
  3. Pilot_FML

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    MTBF's (and MTBR's, MTTF's, MTBDE's etc.) are Reliability Engineering terms measuring different ways of measuring how a part fails over very long periods of time or with accelerated testing. I doubt very strongly that DJI has invested in the engineering staff to track failures for extended periods of time. These failure modes are only usually tracked for military hardware where a customer has deep pockets and can pay for these types of engineers.
     
  4. gianni_BT

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    MTBF is calculated on many civil and industrial equipment :probably it is necessary to follow the Air Ontario suggestion and try to calculate the MTBF from the MTBF data of the motor manufacturers, that for sure have done this evaluation.
    But, coming back on the reason of my question: i fly about 250 batteries in 8 months up to now: do you think I can reasonably continue without be warried about or it is time to think to motor/esc replacement?
     
  5. Pilot_FML

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    My 2 cents.... even if you can find MTBF data for your particular configuration of motors and esc's, I'd still hesitate using the data as my sole decision making source. MTBF's are calculated assuming a consistently repeatable types of usage and don't take into account how often you've wandered outside the units normal operating range. If you've ever crashed, overtaxed a motor, ignored required maintenance, made repairs (or upgrades) to your quad, etc., etc. MTBF's have probably been significantly affected.

    IMHO....continuous inspections and routine maintenance are far better ways to make any R&R decisions.

    Best of luck....
     
  6. Air Ontario

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    Thinking out loud.... I think I would keep up with my personal data and in the mean time search for motor models like are on the bird and see if I could find failure rates documented.
    Short of that I guess I would take specific representative parts(bearings, windings, etc.) and individually look at their hours to failure.

    Then possibly assemble somewhat useful predictive/preventitive maint. ideas.

    Obviously you have made it past the initial curve(infant mortality) and are in the bottom part of the bathtub curve. It would be interesting to see run to failure data from makers.
     
  7. gianni_BT

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    OK: I got that it is not easy.
    So how can I answer my question on when I have to be warried about a motor failure due not to external events(crash etc.) but to "normal" motor and ESC "natural" end of life?
     
  8. gianni_BT

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    From your and Pilot_FML answers I realize that if the MTBF data was not calculated by DJI, it is useless to try to perform this calculation by myself.
    I address to you the same question of my previous post: when should I start to be warried about my bird motors and esc "natural" failures?
     
  9. Air Ontario

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    Nasa did studies, although on small hermetically sealed dc motors, for servos and instrumentation on satellites. Reliability was 94.?% for 1 year of continuous operation.

    I have seen figures for brushless dc motors(although likely larger than DJI) with failure rates above 10000 continuous hours.

    Personally and based on experience and SWAG, I would be concerned that in 2 years or so, the P3P will be less officially supported by DJI if at all.

    I am confident that after infant mortality(on motor, controller and firmware) the aforementioned systems will easily last that 2-2.5 years.

    Obviously changing any of the components inserts infant mortality back into the package again.

    So to answer, I would not be concerned nor do anything other than inspect and keep components from adverse exposure to moisture, dust and impact and expect issues after 2-2.5 years of normal use.
     
  10. gianni_BT

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    Thanks a lot: I will follow your suggestion.