Multicopter motor maintenance?

[Gary Seven]

Hello everyone.

Could some of you cracks advise me on how to perform maintenance on MR motors? I mean, do you need to add a few drops of oil or lithium grease or anything to the motors occasionally? I'm just wondering here. As the motors are the only moving parts of my quadcopter, is there anything I can do to keep them in top form as long as possible? TIA.

 

[gtranquilla]

There is a lot of good information in this topic in various hobby forums. But also some good information from some of the motor bearing manufacturers, e.g., Boca's web site.
IMHO - except for ceramic that do not use lubricant, bearings are packed with powder or fluid lubricant during manufacture for the life of the bearing. But I recall some who will take new bearings and boil them, then add a superior lubricant....... seems like an odd concept to me.

If they start to give you trouble it is best to replace them with equivalent or better. Premature bearing wear can result from dust, moisture, excessive axial loading, unresolved prop/motor imbalance or hard impact causing damage to bearing subcomponents. Also I recall a lot of good info here on MRF from [MENTION=1417]kloner[/MENTION] and [MENTION=1]Bartman[/MENTION] and others.

 

[Jumpy07]

Tiger recommend changing the bearings on the MN motors I have every 60 hours...

 

[kloner]

The motors are the only maintenance there really is..... Bearings are supposed to be left alone per Tigers recommendation.... I used to oil the crap out of them and it becomes a dependency thing if you start and it's messy so you screw up footage doing so. Oil will hit the lens sooner than later.
I've had such crappy luck swapping bearings we just replace motors.... the checklist for a motor is if it has play in any fashion it's smoked. it's gonna flyaway sooner or later because of such. it indicates a broken race or ball bearings or missing retainer clip

 

[Old Man]

I'd been wondering why so many had made suggestions to oil motors with pre-lubed/sealed bearings before use. Glad I never did it.

 

[Holger]

In my mind oiling does not help.
These ball bearings are sealed ( otherwise you would see the small balls between inner and outer half). They are sealed to protect against dust dirt humidity and to keep the lubricant inside.
So any oil you will add sits on top of the seal not entering the bearing and if it does it can actually wash the lubricant out.
Leave them alone, maybe wipe the dirt of here and there, and once they start to become noisy, develop play or have a 'clunk' spot when you spin them, exchange them.

 

[Ronan]

Daily maintenance:
Check wiring
Check connectors
Check motors
Check props
Check flight control system (make sure it hasn't come loose/etc)
Check lipo cells

Only thing that needs to be replaced usually are the motors. Simply swap them.

 

[Gary Seven]

Well ok then, thanks everyone. My take from your collective thoughts is to NOT add oil or grease to the motors. Seems like best practice is to periodically inspect them visually, make sure there's no dirt or objects or whatever jammed in the poles, and check for any "play" of the rotor shaft over time. According to the CW here, if in doubt, replace the motor.

Thanks again to all.

 

[Vortex]

I can understand advising users not to mess with things they do not properly understand nor are properly equipped to properly service but 99% of the bearings used in these motors are not sealed.......They are Shielded and there is a big difference. Sealed bearings have a contact lip seal which makes contact with the bearing inner ring and "Seals" it. Sheilded bearings do not have a contact lip but usually have a pressed stainless steel plate shielding the inner bearing race and it will allow water, dirt and other contaminants in, which ultimately will erode the bearings inner parts causing excess movement ultimately leading to bearing failure.

If your bearings are sealed you won't be able to get any lubricant into the bearing unless the seal is removed or it's already too late and the seal has been damaged but my guess is they are shielded and you can get oil to penetrate past the shield and lubricate it.

You need to remember these are very small bearings and as such only require a very small amount of lubricant. KDE Direct advised me to lubricate the bearings every 300 hours and they have had bearings serviced this way last over 1000 running hours.

I would advise anyone to only take on the job of servicing their motor bearings if they are confident they can do so without damaging the motor or simply replace the bearings with good quality ones, or if you are totally out of your depth then replace the motors altogether.


The lubricant recommended......Triflo

 

[Holger]

Yes you are right the correct term is shielded (English is my second language).
But 1000 hrs on a multicopter?
I doubt that. Maybe in a test lab, but not in real life.
Our kde equipped copter has about 50 hrs and is due for new bearings.
Tiger recommends a change after 60hrs on most engines, 80 on some.
300hrs I'd say is a lot...in real world terms.
In my mechanic years I was always told that ball bearings are greased, so I got curious now and opened (read destroyed) an old bearing. What did I find? Grease, or what was left of it...