Why Aluminium Windings are not being used in Motors ?

(2 Min Read)

• Resistivity of Copper  is 1.68 x 10-8 Ohm
• Resistivity of Aluminium 2.65 x 10-8 Ohm
• Aluminium/Copper  = (2.65 x 10-8) / (1.68 x 10-8) = 1.6

    Aluminum’s resistivity is 1.6 times higher than copper’s resistivity. To compensate, aluminum windings cross-section must have 1.6 times larger and diameter must be 1.26 times of copper windings to offer the same conductance.This means windings wound with aluminum wire will likely have greater volume compared with an equivalent copper wire motor.

    It is possible to match the power performance of a motor wound with aluminum to a motor wound with copper.But since aluminum requires more turns and/or a larger diameter wire,the size of the motor will go bigger, this may not always be feasible in some applications. In situations where efficiency and volume are not issues such as where the motor only has to work occasionally or for very short periods of time, aluminum windings make an acceptable motor.

Cu vs Al