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One motor won't spin after a crash

Discussion in 'Phantom 2 Discussion' started by createthis, Dec 7, 2014.

  1. createthis

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    Hello,

    One of my motors stutters, but won't spin after a crash. The other three spin up. After googling, I thought maybe the motor itself was bad, so I bought a new one from amazon and soldered it in. Unfortunately, the new motor (which BTW, does not look identical - different thickness and mounting foot style) does the same thing. You can imagine my disappointment.

    The DJI Assistant thing doesn't say anything is wrong with the copter.

    Do I have a loose wire somewhere, or is this a bad motor control board, or something else? How do I troubleshoot?

    Thanks!

    --
    Jesse
    CreateThis
     
  2. createthis

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  3. Hughie

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    Yes. ESC. They are not hard to change. In theory the motor could be damaged too but it rarely is.
     
  4. IrishSights

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  5. createthis

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    I know crashes = damage, but that's physical damage. Electronics should not fail electrically because a motor stops. I'm a software engineer, not a hardware engineer, but I know that's poor design. We should design new ESC boards that do not fail in this condition.

    I've decided I'm going to start documenting all of my projects on Youtube. If anyone wants to laugh at my terrible soldering skills and mistaken assumptions, take a look:

    PART 1: http://youtu.be/wpQYWcwoVPQ?list=UUGmXJ ... EBZCH9YRbQ
    PART 2: http://youtu.be/Rk07LxMKrqU?list=UUGmXJ ... EBZCH9YRbQ

    I've got some ESC boards and a flux pen on order. I'll make a PART 3 once the parts arrive and I've had time to brush up on how to solder wires to boards properly. :D
     
  6. IrishSights

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    I appreciate what your saying, however electronics can be damaged too as a result of a crash. That's not a reflection of the quality of the build more a measure of the 'quality' of the crash.
     
  7. RDCF550

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    Your front/left motor is the one not working in the vid, not back left, I can see why you crashed. ;) Just poking fun man.

    Your stock motors are the newer upgraded ones, and your ESCs are also, so make sure that you get the V2.0 one for your replacement, the one in your link is correct, you wouldn't want the V2 one which looks identical. Also, put your old motor back in as I doubt anything is wrong with it, then if it is bad with the new ESC get the same newer style motor to replace it. The newer ESC doesn't have the last 4 sets of beeps on power up. Plenty of vids and such around to compare yours to that only have the first set of beeps. You will also want to check and make sure the motor is spinning in the correct direction after wiring it back up, and if it's wrong just swap any 2 wires you feel like to correct that.

    Your props only need to be spun on by hand, and then just barely snugged by hand to make sure it's on there all the way. A crash can/will also crank those things on tighter as well. They make a tool for holding the motor still, as you don't really want to be sticking things into it as it could damage the windings.

    If you want to code up an ESC to shut down under too much of a load so that it 'might' save it's output FETs in a crash, you also run the real risk of that happening during a perfectly normal flight where one motor is just working harder to keep things level and drawing more current than usual. That's a really fine line to walk when only dealing with the ESC and current draw as your sole source of input for what is going on with the thing. If you also had access to the Accelerometer, Gyro and Barometer data and such, you could tell if the P2 was just trying to right itself or if it was sitting still trying to right itself, which is where most ESC boards get toasted as a prop is jammed on the ground or up against something else and can't spin.

    viewtopic.php?f=5&t=28252

    The only thing I've seen fail so far on these things are the output FETs, and while they're not easy for the typical user to replace, it costs less than half of what a new ESC does if you can. They tank in the event of crashes as the prop gets stuck on something and can't move, but the Phantom is trying like mad to right itself. Since the prop can't spin and use up that current, all of it just ends up nuking one or more of the output FETs. A little more practical solution is a kill switch for the ESCs, as that CSC command takes far too long to be of any real use in the event of a crash or fly away as those few seconds count, but then you run the risk of the average user hitting that thing by 'mistake' all the time and dropping their P2 out of the sky when nothing is wrong causing damage that otherwise wouldn't have happened.
     
  8. CityZen

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    Designers could add current sensing to the ESC microcontroller. This would be extra circuitry, hence extra cost. But maybe there's a market for it.

    Or, it may be possible to write obstruction-sensing routines in the microcontroller firmware. This seems like the best solution, since it's "free" once the software is developed.
     
  9. createthis

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    PART 3 of the series: http://youtu.be/FoQVgofwTsg

    I incorporated a few of the suggestions from here and deliberately ignored others to see what would happen. It's a little long, but check it out. The new ESC boards say "2.0". The old ones didn't. They look like they have a higher release number too, near the motor pins, if that's what that number means.

    You might notice at the end of the video that the new (older version) motor spins slower at idle. Interestingly enough, it works fine in the air. I'm not sure if that's the motor or the ESC's doing.
     
  10. Hughie

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    In Part 1, you offer "a little tip" to remove a prop. :eek:

    I really dont think it is a good idea to have an instructional video on line which offers tips encouraging wedging allen keys into motor housings. There is a tool available for a reason. :(
     
  11. createthis

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  12. RobertMfromLI

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    Incorrect. My older ones say "2.0" but do not have the revised firmware (and the firmware for the ESCs is not end user upgradeable).
     
  13. createthis

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    What's the difference, practically?
     
  14. createthis

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    In the photo above, the ESC on the bottom is the broken one that came out of my Phantom 2. The one on top is from Amazon. Note the higher serial number and "2.0" markings. You're telling me the ESC on top is running an older firmware?
     

    Attached Files:

  15. RobertMfromLI

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    Which sadly, we determined, mean nothing. It's all about the firmware, and not about the markings. And the markings do not correspond to the firmware.

    Check this thread here:
    viewtopic.php?f=19&t=29938
     
  16. createthis

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    Ok, that's interesting, but what does it mean? The phantom flies. Why should I care which version of ESC it's running? As long as the phantom carries the weight of my gimbal and gopro, I think I'm good.
     
  17. RobertMfromLI

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    Yep, you're all set - I just didn't want you to pick up the wrong board (didn't realize when I posted that you've fixed yours), or anyone else following the thread to make the mistake of thinking that the labeling mattered, since it doesn't.