That's the Koito power window motor that the Banawe repair boys in front of the Orthopedic Hospital gave back to me after replacing. I repaired it with nothing more than a kitchen knife. That's quite a lot of money wasted ($40 plus). So they rewound it for nothing, and replaced it, again for nothing.
There was nothing wrong with the wretched motor, even though it was missing one brush. The plastic worm wheel had damaged teeth, that was all. Hence the thing was jamming. It was so blindingly obvious when I opened up the worm gear assembly that the worm was binding on the plastic worm wheel. I guess it's not so obvious to the Banawe repair boys.
I just cut down the damaged teeth with a kitchen knife and it now rotates freely. And too fast for my astrophotography barn-door mount. Oh well, at least now I have a spare power window motor.
And more importantly, I can now repair any of the power windows if ever they get damaged.