how to tell if a motor is going to fail

[JLO]

Does a motor has signs that its going to fail, is there a distinct sound, or feel when turning them by hand that it could fail that its better to change it than to risk it fail in mid flight I have DJI motors on a F550

thanks

 

[jes1111]

Basically - any change in sound or feel should be investigated and corrected.

 

[apeman88]

For most brushless motors... the bearing will go first. You will hear the bearings making grinding weird noise... then it's time to service the motors or replace them. If memory serves, most brushless motors are rated at about 1000hrs +/-.

Ken

 

[jes1111]

brushless motors are rated at about 1000hrs +/-

... or until the first prop strike, whichever occurs first

 

[animau]

and for the dji f550 stock motors what bearing do i have to buy to replace it?

 

[Bella7821]

Here are the bearings you use for stock DJI motors
http://gothelirc.com/shopdisplayproducts.asp?id=122&cat=Bearings
ABEC5 3x8x4 mm bearings (2x)
sku: S693ZZ

Replacement bearing for DJI 2212 motor.

Don't mix up with other bearings! These are the highest quality stainless ABEC-5bearings.
ID: 3mm
OD: 8mm
Thickness: 4mm

Quantity: 2
​

ABEC1	ABEC3	ABEC5
.015	.007	.005

 

[winstongotte]

took a prop strike in a tree last week. motor took a nap. but at 23.00 i put a new one in and back to tearing up the skys.

 

[hover]

Don't mix up with other bearings! These are the highest quality stainless ABEC-5bearings.
​

Just dont mix bearings on the same motor or the whole quadrocopter? Maybe the 4 motors could spin slightly different with different bearings.​

 

[jes1111]

Here are the bearings you use for stock DJI motors
http://gothelirc.com/shopdisplayproducts.asp?id=122&cat=Bearings
ABEC5 3x8x4 mm bearings (2x)
sku: S693ZZ

Replacement bearing for DJI 2212 motor.

Don't mix up with other bearings! These are the highest quality stainless ABEC-5bearings.
ID: 3mm
OD: 8mm
Thickness: 4mm

Quantity: 2
​

ABEC1	ABEC3	ABEC5
.015	.007	.005

Stainless steel ABEC5 bearings for US$1.45 each? Really? :nevreness:

 

[Batfire]

Hmmmm.......

Good question. I have a motor that went on my X830 quad and those are dynamically balanced kv650 motors ($70) a pop. Anyway it momentarily failed in flight causing the death flip. Luckily no real damage was done only a few feet off nice grassy area. I took the motor apart and found a small washer that looks like it had been in there since day one.
I put the motor back together and ran and within a few minutes it momentary quit again. Then you can start it right back up. No bearing noise, bearing turn and look fine and see nothing wrong with inside of motor, all wires well connected and even tested them with meter to make sure ok. So I have no idea what is wrong with motor. Since these come with motor mount as part of motor assembly just put it in spares bin.View attachment 5675

 

[apeman88]

It might be a almost break or short on the windings. Those wires are coated with super thin insulation material and are heat rated. If the motor runs above rated temp... It will melt the insulation resulting in a short or act as a fuse and break.

Ken

 

[Batfire]

Hi Ken

I have never run motor hot, I monitor this closely since doing evaluation of X-830-H quadcopter. I, as mentioned earlier did find a tiny washer in motor which was rubbed very smooth so sure it’s been there since factory new. Now as far as the windings honestly I can’t tell my multimeter doesn't show an issue but that doesn't mean there is not one.:black_eyed: Obviously or not so obviously the washer could have caused the issue you mentioned and I just cant visually see the damage.:apathy:

See blog. http://www.rcgroups.com/forums/showthread.php?t=1670862 Tutorial number 4 and you can see what I have been going through on this quad. I guess the only real thing I could do to find issue is send motor back to manufacturer. Like I would ever get an answer from china or see the motor again.:dread:

Thank you for your comment though.