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Motor Balancing Question

Discussion in 'Phantom 2 Vision + Discussion' started by phalcon51, Feb 22, 2015.

  1. phalcon51

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    After balancing my props I'd like to check the balance of the motor end-bells to ensure the longest bearing life and smoothest video possible. I was wondering if anyone knew the best way to go about it. Specifically, is there a way to isolate power to one motor at a time so I can run it through the rpm range without doing any damage elsewhere? (Haven't looked yet so I don't know if there are any ESC plugs that can be disconnected or whether the system will even power up with any of the motors un-powered). I want to utilize an app on my iPhone to visualize any vibrations present at each motor arm and correct any imbalance present.

    Thanks for any help.

    Gary
     
  2. phalcon51

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    Before my post gets lost in the shuffle from pg.1 to pg. 2, does anyone know if it's possible to isolate one motor at a time, electrically?
    Will the system initialize so the throttle will work on the isolated motor?
    Any possibility of doing any damage?

    Thanks
     
  3. phalcon51

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  4. flyNfrank

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    Answer is...no. I came in this thread hoping to find out how to balance the motors.
     
  5. Fplvert

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  6. Mori55

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    Don't you think that's overkill ? If I had jello and balancing the props didn't work I'd worry about.
     
  7. CityZen

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    Running one motor at a time is easy: just unplug the other ESC control signals.
    However, those other ESCs will beep without a control signal.
    You can throttle up one motor just by tilting the right stick towards a corner.
    But in any case, you can also feel a motor that's off-balance enough just by holding each motor mount firmly.
    And, of course, if you want to balance it, you need to do something like shown in the video above.
     
  8. phalcon51

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    CityZen,

    Thanks for the reply.

    Can you be more specific on where to find the ESC control signal wires? Do they plug into a main board in the center? (haven't really looked inside yet in detail)

    Re: the video linked above - this won't work on the P2V+ v3 as that technique relies on threading the barrel from the disassembled center punch tool
    onto the prop threads of the motor end-bell. This will only work on the 2 end-bells with RH threads for the newer Phantoms with the self-tightening
    props.

    The way I plan on balancing them is to wrap a small, thin zip tie around the bell, run the motor and monitor the vibration level with an app called
    myIseismo on my iPhone while it's being held against the motor arm. You just twist the part of the zip tie where it connects to itself to different locations around the bell and monitor the vibration level. When you find the point with the lowest vibration level, this indicates the lightest part of the bell. The next step is to then apply a small piece of copper tape at this location to counterbalance the heavy point of the bell on the opposite side and then retest. It's trial and error at that point to determine the size of the copper tape. Once finished balancing all four motors you then mount one (balanced) prop at a time and retest the vibration level of that motor/prop combo. You can find several YouTube videos describing this technique by searching for "Brushless Motor Balancing".
     
  9. jarance

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  10. CityZen

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    For the reverse-threaded motors, you can use a tube that fits snugly over the threads.

    If you google "dji phantom 2 inside", you can look at the pictures and see the cables that connect the ESCs to the main board.
    There is a power cable and a signal cable.
     
  11. jumanoc

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    Here is how to I did using my phone with Vibrometer App.
    https://www.youtube.com/results?search_query=balancing+motor+with+a+vibrometer

    Also you can use a laser pointer technique:
    https://www.youtube.com/results?search_query=balancing+motor+with+a+laser
     
  12. phalcon51

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    Thanks for the link, I'll look into this.

    Gary
     
  13. phalcon51

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    The problem with that is there is almost certainly to be some slight degree of misalignment between the prop thread shaft and the pressed-on tube making the two shafts out of true with each other. This will create a false imbalance and make balancing the bell accurately next to impossible.

    Gary
     
  14. phalcon51

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  15. jarance

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    Not sure whether you can unplug 3 motors and use the RC controller to "test" one of the motors.
    The NAZA might disable the "take off" when it detect some of the ESC are not connected (fail safe mode). (Will give it a try the coming weekend.)
    However, you might encounter some problem to get a constant speed. Please be aware that vibration amplitude changes with speed.
    You want to balance your motor at a certain speed and i foresee you will end up with more problem if you use the RC controller.

    Get a ESC tester from China (AliExpress). They are relative cheap and It work much better and you can replicate the speed.
    As for the vibration monitor, you can use a smartphone with the Vibrometer App to see the vibration amplitude.
     
  16. Meta4

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    Seems like a lot of effort that is probably unnecessary.
    Is there any reason to suspect that the motors might be unbalanced?
     
  17. phalcon51

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    Is the ESC tester a "Plug 'n Play" proposition? Just unplug the ESC from the Phantom main board and plug it into the tester? I assume the knob controls RPM?

    Gary
     
  18. happydays

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    I'm not at home so can't check - but I seem to remember that it was possible in the assistant software to run each motor on its own to test the direction of rotation for example. Maybe I imagined it.
     
  19. Mori55

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    As I said before this is overkill. If you don't have vibration or jello problems why do it ? These motors last for a very long time and if you damage them they're chesp to replace.
    Must be winter boredom setting in.
     
  20. CityZen

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    If your Phantom vibrates a lot when you run the motors without propellers, then you might want to look into this. If it doesn't, you can probably ignore this.