Harman XXV distribution blower

[civilkane]

Upon removal and dismantling the distribution blower after experiencing no flow and squealing, i discovered that the shaft to which the blower wheels is attached is not secured to the rotor. Further, there is evidence of high temperature coloration on the shaft. The motor runs, but fans are still. How is the shaft supposed to be connected to thevcd rotor? Motor appears competent.
By the way, I have replacement on the way but am curious as to how common this is.

 

[Ssyko]

There is usually set screw that tightens up the fan balde to the shaft

 

[Mt Bob]

The original blower(a tangential blower) would have been an EBM/PAPST.the 2 blower "wheels" would be a press fit onto the motor shaft.If they "spun out",loosened up,could only be from 2 things,the outer bushings(which are oilable),seized,or long period of time with the fins on the blower wheels creating excessive drag.Problems like yours usually come from having cats or dogs,and not vacuuming the blower enough.