The fan housing seems to be a very hostile environment for the electric motor bearings (or the motor is underdesigned for the application)
At best, we seem to get 2 years use out of the airconditioner before the bearings lock up.
The first two times the motor was replaced under warranty.
Then we paid $340 ourselves the next time.
Following on from that, the next time it failed, I finally I twigged that all it needed was a set of $18 bearings replaced.
This is the second time I've replaced the bearings myself - so that's 5 failures in 11 years.
It's about an hour to pull the motor out and break it down, and about an hour to put it back in again.
Of course - it always seems to fail over the Christmas / New Year break.
Fortunately we have a little "through window" unit that just manages to keep the house bearable while the main unit is out of action for a few days.
Bearing part number is NTN 6202 LLU/2AS
In the last image, the wires entering from the right of the picture are from the motor cable.