In the case of a 3 phase PMA radial flux type, used as a wind turbine, with magnets on the surface of the rotor, is it safe or even doable to stack another magnet with the same geometry on top of the existing ones, to reduce the air gap ? (supposing that the air gap is poorly designed in the first place by being way too large).
I suppose that the current magnets are glued to the rotor frame by epoxy. It would be cumbersome to knock them off easily.
The new magnets would be glued with epoxy too on top of the first layer.
The main problem I would see in this case is that a reduced air gap may cause the rotor to seize by striking the stator poles due to axial tilt in case of high vibrations / high RPM. or, the added magnets becoming loose at high RPM.
Any other mechanical issues to consider besides higher torque ?
In case of performance, I would expect higher starting speed and overall lower RPM at a given wind speed, lower destructive RPM tolerance, but higher power output and overall higher efficiency.
Anything I should take into account besides higher EMF at a given RPM for my rectifier circuit ?