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Motor Problems

Discussion in 'General Discussion' started by Jack87, Nov 24, 2013.

  1. Jack87

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    Hi Everyone,

    I've had my phantom a few weeks now and done a number of successful flights with it, no crashes or impacts. I've just noticed after landing today that my front right motor stopped a lot faster than the rest when the motors were powering down. When looking closer, the motor is not spinning smoothly. when spinning it by hand it doesnt have the same smooth feel as the other three and it feels like its slightly grinding on something? I'm about to open up the shell and see if anything has got inside (although im not sure what it could be)

    Has anyone come across this before or have any idea what it could be?

    Thanks

    Jack
     
  2. cptdarel

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    Pull the cover to make sure it's not hitting the housing, re-spin, and check bearings for failure.
     
  3. Jack87

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    With the motor in question, I can grip it with my fingers and it can rise up slightly and when spun like that it sounds smooth. However with the other ones they cannot be pulled up in the same way.....if that makes sense?

    Cant find my little screwdriver to take it fully apart so will pick up a new one tomorow!
     
  4. The Editor

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    By the sound of what you describe you have lost the e-clip (as well as the associated thrust washer) that holds the motor pinion in place.

    The e-clips are easily sourced, they are 2.3mm (but 0.6mm thickness). the thrust washers are harder. You can make yourself one out of a 3mm washer but you will have to grind down to the right thickness.

    Alternatively you will have to buy a set of e-clips and thrust washers from Fleabay or similar but you will probably have to buy a complete set with new bearings (not that that is a bad thing since the original DJI bearings are really crap)

    Something like this ----> http://www.ebay.co.uk/itm/DJI-Phant...pt=Radio_Control_Vehicles&hash=item3cd60e8a31
     
  5. Jack87

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    Thanks for that. I took the lid off to have a closer look a the motor. There was one of the e clips had come off from somewhere and was stuck in a place it shouldn't be. I got the e clip out and now the motor turns smoothly again like the other.

    Not knowing much about motors, is this tiny e clip something that needs to be put back in the right place?
     
  6. The Editor

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    Yes - the e-clip should fit into the groove on the bottom of the motor shaft with all three points of the e-clip locating in the groove channel. Importantly though there should be a thrust washer on the shaft of the motor which gets sandwiched between the e-clip and the bottom bearing when everything is fitted properly. If you have lost this thrust washer when you place the e-clip back you will still get play up and down when you try to lft the bell of the motor as you dis before.
    Each motor MUST have a thrust washer and an e-clip in place.
     
  7. Jack87

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    Bugger. Yes there is some play up and down like there was before still. I will open it back up tomorrow and have a look for the washer. Lord knows how its fallen off. Ive never had any sort of impact and have only had maybe 10 flights on it!
     
  8. jthorstad

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    Is this some manufacturing defect? Mine just did this today as well. Had it three days.

    Now that I cleared out the e-clip the prop spins freely. The magnetic pull of the motor holds that sucker on there tight.

    I flew it a few feet off the ground after fixing that, but didn't press it.

    I suppose impending doom is around the corner flying it like this?

    Seems like a real weak link in the manufacturing process? Does DJI do anything about such things?
     
  9. jthorstad

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    I found the washer, but no e clip. Might these be available at a Home Depot or something like that, do you suppose?

    Thanks for all the great info on this issue!
     
  10. jthorstad

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    Update: I found a couple e clips at NAPA. Whew.

    Now I see that the shaft for this particular prop was installed incorrectly at the factory. It's not long enough for the washer (which looks more like a brass barrel than a washer) to fit and expose the groove for the e clip.

    There is a hex nut that will allow you to adjust the shaft length, but I don't have the correct wrench for it. Bummer.

    For now I've put an eclip on without the washer. There's just a little bit of play when I pull up on it. It flies, but the video I just shot seems to have a lot more noise in it than I got on other videos.

    I suspect that the eclip on this prop was NEVER properly seated as it left the factory, and just a small bump was enough to jar it loose.
     
  11. Jack87

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    I have just investigated mine further. I have the e clip but no thrust washer. Does anyone know somewhere in the UK that I can get some thrust washers? I'm thinking I'll just buy a backup motor.

    In the mean time I have put the E clip on with no washer. It seems to rotate fine.

    Does anyone know the dangers in flying like this with no washer on?

    Thanks for all the help, opening it up has been a real eye opener and I have learnt a lot!
     
  12. jthorstad

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    Jack87 - what did your washer look like? Flat, like a regular washer? Or was it more barrel-shaped?

    I was surprised at the shape of it considering it's called a "washer". It seems more like a "spacer" to me.
     
  13. The Editor

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    The thrust 'Washer' or spacer or shim is a small alloy washer that takes up the space between the e-clip on the shaft and the face of the lower bearing on the motor.

    The purpose of it is to transfer load from the bottom to the top bearing so that there is equal loading on both. If you operate the motor without the thrust washer in place you are transferring lateral forces onto the lower bearing (through the lift from the props) and this will cause the bearing to fail quickly. The bearings that DJI supply are very poor quality in any case without undue extra load being applied to them :shock:
    I replaced my bearings very early on with ceramic bearings which are maintenance free, have much tighter tolerances and are far more robust than the cheap Chinese ones in the Phantom.

    If it was my Phantom and I had lost an e-clip and thrust washer - while I had the thing apart I would just replace all the bearings, clips and washers and be done with it.
     
  14. Jack87

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    My washer was missing! Hells knows where its gone as its only had maximum of 10 flights with smooth landings every time! I'm struggling to find any place that sells these washers or even a uk dealer for the full kit that sells bearings and e clips. All I need is the bloody washer!
     
  15. Ruff Ryda

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    Location:
    Harrisburg, IL
    I found that on one of my motors that the washer was too thick and made the motor bind and the e-clip nearly impossible to install. I sanded washer/spacer to give me more clearance. Now that motor spins freely and the clip is muck easier to install after maintenance.
     
  16. jthorstad

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    Hey Ruff Ryda! How did you sand that little sucker?? I'd be willing to give that a try before I throw in the towel and return mine.

    Those things are so dang small, and so impossible to find if they fall anywhere! I'd love to hear how you did it! Thanks!
     
  17. Ruff Ryda

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    The stock spacers are brass I believe, so I used an emery board(1500grit sandpaper will work too , if not better) and it worked just fine. I laid the board flat, set the spacer on it and used my finger tip to move the spacer back and fort on the board. It takes a little while to get it down to the right size but, slow and easy keeps you from removing too much material.

    I would keep checking through the process to insure that you remove just enough to allow installation of the eclip only.