One motor bearing doesn't spin as smoothly as the others

[steambuddy]

It is also hotter to the touch after test flight. Props are brand new just replaced official DJI props bought from Best Buy 1 day ago.

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[lannes]

maybe try blowing it out with some compressed air or hurricane blower Hurricane - Canless Air System - Canned Air Alternative

 

[steambuddy]

maybe try blowing it out with some compressed air or hurricane blower Hurricane - Canless Air System - Canned Air Alternative

Just tried that with no improvement

 

[Mossiback]

Could be hair or something else wrapped in the motor. Take the props off and use a magnifier for a close look. Try turning it over and rapping lightly on the motor housing with a screwdriver to dislodge solids. Compressed air might help dislodge something but also might push it in tighter.

 

[bumper]

With the prop off (much easier to feel what's going on), using thumb and index finger, you can turn the motor rotor to feel the friction. A gritty, uneven feel could be some sort of debris between the outer housing (magnets) and the stator (windings core). Try wiggling the housing back and forth (radially), there should be no play.

 

[steambuddy]

With the prop off (much easier to feel what's going on), using thumb and index finger, you can turn the motor rotor to feel the friction. A gritty, uneven feel could be some sort of debris between the outer housing (magnets) and the stator (windings core). Try wiggling the housing back and forth (radially), there should be no play.

There is play. It's a subtle notchy feeling

 

[Mossiback]

With the prop off (much easier to feel what's going on), using thumb and index finger, you can turn the motor rotor to feel the friction. A gritty, uneven feel could be some sort of debris between the outer housing (magnets) and the stator (windings core). Try wiggling the housing back and forth (radially), there should be no play.

It could also be hair or something else wrapped in the motor. This would not feel gritty or uneven, but would cause more drag on the motor.

There is play. It's a subtle notchy feeling

Does it feel the same with the other motors? If not, perhaps you have a worn bearing. Never heard of it happening but bearings can wear out. Does the prop sit at the same height away from the housing as the other three?

 

[steambuddy]

It could also be hair or something else wrapped in the motor. This would not feel gritty or uneven, but would cause more drag on the motor.

Does it feel the same with the other motors? If not, perhaps you have a worn bearing. Never heard of it happening but bearings can wear out. Does the prop sit at the same height away from the housing as the other three?

I crashed it 2ft above ground against my car and the propeller chipped. But I don't see any debris inside. Is this something of high priority or can I keep flying like this?

 

[old man mavic]

check the prop that came off that motor to see if any of the small lugs that hold it on have broken
the other possible issue could be a slightly bent motor shaft from the impact or a magnet that has moved due to the impact
you should not really keep fling with it like that as if it fails while you are flying then it could spell the end of your drone and worse still cause injury or damage depending where it crashed

 

[steambuddy]

check the prop that came off that motor to see if any of the small lugs that hold it on have broken
the other possible issue could be a slightly bent motor shaft from the impact or a magnet that has moved due to the impact
you should not really keep fling with it like that as if it fails while you are flying then it could spell the end of your drone and worse still cause injury or damage depending where it crashed

Should I replace the whole arm or just the motor? Also, just did a test flight and checked temps of each motor and none exceeded 110 F. Is that a good sign?

 

[old man mavic]

Should I replace the whole arm or just the motor? Also, just did a test flight and checked temps of each motor and none exceeded 110 F. Is that a good sign?

the arm and motor come as one piece so you would be replacing the arm

 

[bumper]

Replacing the arm requires some mechanical aptitude and soldering skill. I actually saw one video where the "DYI repair tech" was using a Weller "transformer type" soldering gun (You *never ever* use that type of soldering gun on solid state electronics. The tip of the gun is actually the secondary of the transformer and it has very high current to heat the tip. This can inductively couple into circuit traces and components, damaging them). A pencil iron is the appropriate tool. - Rant off.

 

[bumper]

There is play. It's a subtle notchy feeling

Okay, the notchy feeling, depending on "which one" :c), is the magnets going past the armature core of the stator, and is, when turning the motor rotor slowly, felt as resistance, then push, then resistance again that is consistent in its degrees of arc. A failed bearing or debris would not typically be so precise.

Look closely at the gap at the bottom of the outer rotor "shell". If the motor shaft is bent, then this gap will be wider on one side of the motor than the other - The difference may be slight, depending on severity of the bend. You can also check for this by running the motor without prop, and resting the shaft of a plastic spoon or popsicle stick against the end of the motor shaft - check for vibration at the distal end.

 

[steambuddy]

Okay, the notchy feeling, depending on "which one" :c), is the magnets going past the armature core of the stator, and is, when turning the motor rotor slowly, felt as resistance, then push, then resistance again that is consistent in its degrees of arc. A failed bearing or debris would not typically be so precise.

Look closely at the gap at the bottom of the outer rotor "shell". If the motor shaft is bent, then this gap will be wider on one side of the motor than the other - The difference may be slight, depending on severity of the bend. You can also check for this by running the motor without prop, and resting the shaft of a plastic spoon or popsicle stick against the end of the motor shaft - check for vibration at the distal end.

I just tried that and the CW motors had the same vibration levels. The CCW motors had different vibration but no difference between the top left motor and the other one one spinning the same way. I don't have a vernier caliper to really measure the gap difference but to my eye is unnoticeable. I just did another test flight and it does run 10 degrees F hotter than the rest.

 

[SpitFire]

That would be a good indicator, to check temp in each motor. They all should be consistent, as far how hot they get. I use a RYOBI, laser hand held gun to check heat on motor, heat sink. Motors will usually start making some strange mellitic sound before failure. If you spin them gently by hand you can feel extra resistance. Getting hotter, then the rest, could be a indicator, of future trouble.
I take temperature of each one, while blades spinning with my laser gun. Just to check before flight, that is just me, I treat it just like a full size plane before take off.

 

[steambuddy]

That would be a good indicator, to check temp in each motor. They all should be consistent, as far how hot they get. I use a RYOBI, laser hand held gun to check heat on motor, heat sink. Motors will usually start making some strange mellitic sound before failure. If you spin them gently by hand you can feel extra resistance. Getting hotter, then the rest, could be a indicator, of future trouble.
I take temperature of each one, while blades spinning with my laser gun. Just to check before flight, that is just me, I treat it just like a full size plane before take off.

I hadn't thought of checking their temperatures while they're spinning, that's a great idea. Thanks for letting me know there will likely be an audible indicator of failure before it happens.