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P3P motor locked up during flight

Discussion in 'Pro/Adv Discussion' started by Crappiefisher, Oct 11, 2016.

  1. Crappiefisher

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    Sadly my drones front motor (2312a CCW) locked up after take off falling about 50 foot. The prop spun off when motor locked up and drone spiraled to the ground. The gimble was bent and case cracked in several places. I've ordered replacement shell and motor since DJI was no help. Seems like this has happened to several others. Luckily this was in my yard and I don't fly where a fall would be critical. Don't know if I can put any faith in this drone again.
     
  2. Crappiefisher

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    I should mention this drone has never had a tip over or collision in 7 hours of flight and 71 miles.
     
  3. BigAl07

    BigAl07 Moderator
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    Hello [​IMG]

    Welcome to the forum and the addiction er hobby :)

    Hate to hear about your incident but this is part of flying them. The basic rule of thumb is the only ones that don't crash are the ones we don't fly. Our "quads" have on redundancy built into them and if a motor, prop, ESC etc fails it's coming down in an uncontrolled fashion and quickly.

    The components on these aircraft are good but still hobby grade, uncertificated, and made in a country where quality control can be questionable.
     
    jnix, GPSMapNut and forshiggles like this.
  4. Mocho

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    Welcome to the forum!
    How did you determine the motor locked up, then the prop spun off?

    Just curious...
     
  5. N017RW

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    Sounds more like an ESC failure as the only moving part in the motor is bearings. If the motor is able to be rotated by hand without resistance or any roughness it sounds more like an electrical failure.

    One way to be sure is to swap motors to see if the failed motor works on a different arm (ESC).
     
  6. Crappiefisher

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    The motor would spin backwards but stops (like anti reverse in a fishing reel) when spun it's normal rotation. An ESC failure wouldn't necessarily lose a prop would it as the motor would free spin? Also it appeared to be a single motor failure as the drone spiraled as shown in the log and only the single prop came off. I always snug them on and there was no damage on the one that came off.

    Thanks for the advice on troubleshooting but this motor is getting replaced. I can't see anything in it but didn't fully disassemble yet. I can see how anything would even get in the motor as I keep it in a hard case.
     
  7. Roamer105

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    Do we know how the phantom executes power braking?


    Sent from my iPad using PhantomPilots
     
  8. Crappiefisher

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    I'll disassemble the bad motor once I get the replacement installed. Something is giving it a hard stop when try to spin it CCW which is it's normal rotation. Maybe it is a bearing failure and there is a piece inside.
     
  9. HWCM

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    It does not have it.
     
  10. HWCM

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    I have seen this before when one of the magnets come loose inside the motor housing. Not on a Phantom, but another build I have done.
     
  11. Crappiefisher

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    Seems like magnets or bearing issue. Can't see into the motor enough even if there was a broken magnet chuck floating around.
     
  12. N017RW

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    The P3 has some sort of brake or rotation damping feature.
    DJI may call it 'air braking' or some other marketing description.

    Of course there are many ways to achieve this and the extent is also debatable but some type of enhancement exists.

    This is the reason for the composite hub on the P3 props as compare to the P2s.
     
  13. flyNfrank

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    That is not correct. It's not called Power Brake but rather Air Brake. I have adjusted the settings on mine to to not stop suddenly, or as much.
     
  14. HWCM

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    Ugggg...Here we go again...If you say so. I will leave it at that. I really do not feel up to going through this again.

     
  15. With The Birds

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    I think we are talking about "Active braking"... apply an electrical load to a motor (resistance between the stator field coils in the case of the phantom motors) while they are running with the electrical input removed and they will slow faster than if left to spin down open load. As the phantom propulsion system is sine wave drive rapid deceleration would also be possible by reducing the line frequency allowing deceleration at a precisely controlled rate as commanded by the flight controller. While both are possible I suspect the later is employed as there are seemingly no dummy load resistors in the ESC circuit. It is possible that regenerative braking could be employed. however it is implemented the phantoms do have active braking.
     
  16. Crappiefisher

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    Finally able to do a test flight and use a full charge with no issues. Gimble needed .4 adjustment on roll.

    Didn't get the motor disassembled yet to diagnose it.