I had two sticky motors after 4 dives with my Trident. One in fresh water the remaining in salt water. OpenROV sent me 2nd gen replacement motors and everything is now honky dory.
The replacement motors look exactly the same. What is the difference between 1st and 2nd gen?
The motors are easy to disassemble so of course I did so with the old ones. The two sticky motors had a bit of rust inside. The materials specifications for these seem to not have included resistance to rust?
One of the rotors had developed a small bulge on the inside effectively preventing the motor from rotating.
Two of the motors did not have a washer between the clip and the bearing, something for QC to address?
(I did not check the ones I installed, maybe I should take them apart and check?)
The stators looked fine to the extent that maybe OpenRov should offer boxes with replacement parts, then you can fix the motors in the field and no use to wait for replacement motors. The motors are identical except for the length of the axes and the base plate (fixing is better than throwing away:)).