Fan wheel

The motor/fan unit from the bottom. Note the evidence of dynamic balancing on the fanwheel (the bolt, ground off casting bosses etc) and the nice expansion ramp with silicone sealant. 24" scale gives some idea of just how big this is. The outlet (at right) has a nicely cut (plasma? laser? water jet?) grill to make sure no large pieces of high velocity material can attack the filter.