Yes
I don't think so, because of the large currents that I am measuring.
...
The temperature sensor is on the side of the motor. There could be circuitry that reads it on the board, but I do believe that it does overheat, from the currents I measure.
No - I haven't let it run very long.
The vac plus the connected load can't exceed 12A. Maybe the sensor on the motor is a switch that interrupts both & its limit is 12A.
The neighbor has experienced shut-off with no connected load.
I've never felt very strongly that the bearings are the problem - they just don't seem tight enough to cause that much draw (5.6A on low speed vs 2.9 spec'ed). But it was the only thing that I thought of.
Another thing that I just thought of was damaged field winding. I.e., adjacent turns shorted, reducing the field, and drawing more current. I don't know if that makes sense, if it ever happens, or how to test for it.
The motor-fan unit has fragile fans pressed on both ends, has a housing that is glued or heat-welded together, and is just not going to be explored. I'm about ready to pull the plug and have the neighbor order a new one.
Bob