Tesla makes two kinds of electric motors. Their oldest currently-produced design is a three-phase four-pole AC induction motor with a copper rotor[1] (which inspired the Tesla logo), which is used as the rear motor in the Model S and Model X. Newer, higher-efficiency permanent magnet motors are used in the Model 3, Model Y, the front motor of 2019-onward versions of the Model S and X, and is expected to be used in the Semi .