If your micro motors start making noise it could be a sign of worn out bearing, or it could just be dry, lubricating the bearing might help improving the smoothness and efficiency.
I thought we shouldn’t lubricate brushless motors?
It’s true that we don’t have to lubricate brushless motors with ball bearings. Ball bearings are sealed with grease inside, so applying oil doesn’t really help much but actually could be counter-productive as well as making a mess because oil will attract dusts and dirt.
That’s a different story when it comes to micro motors such as 0603 and 0703, as they don’t have ball bearings but brass bushings (sintered bearings), which creates way more friction than ball bearings, not to mention they run at extremely high RPM and that only makes it worse. Oiling them reduces friction and help them run smoother! This makes more noticeable difference on lower quality motors.
Benefits/Downsides of Oiling Micro Motors
- runs smoother, less vibration to gyro
- more efficient and longer flight time
- better longevity
The downside is it will get dirty easily, espcially if you fly in dusty environment as oil will attract dirt. If you are happy with how your drone flies, you don’t need to oil it.
What Oil To Buy?
Preferably synthetic bearing oil with a needle tip for easy apply inside the motor: https://amzn.to/2V4sFaE
How to do it?
- Put the motor at 90 degree facing yourself, apply a tiny drop on the shaft inside the motor bell just above the stator
- Slowly turn the motor by hand and let the oil run around evenly on the shaft
- Turn the motor over, and apply a tiny drop on the bottom shaft / bearing too (if it’s a ball bearing, don’t do it)
- Now put some paper towel under the motors, arm the quad and let the motors slowly spins for a few seconds until there is no more oil dripping from the motors
- You might want to fly your first flight outdoor, just in case oil splashing everywhere :)