There are some problems with the use of aluminium.
Aluminium can used in motor windings but generally have a lower heat dissipation factor. Once again these windings would be larger, thus making the entire motor larger.
The other problem is aluminium cannot be used in industries that must be "intrinsically safe" such as coal mining, due to the gass ignition and the high temerature spark that aluminium creates. Coal miners cannot even take aluminium cans underground. Only a small selection of industries must be "intrinsically safe" but these industries will always use copper whilever this regulation stays in place.
