Do Tesla cars use AC or DC electric motors?

You're asking about the technical tradeoffs surrounding the selection of a traction motor for an electric vehicle application. Describing the full design tradespace is far beyond what can reasonably be summarized here, but I'll outline the prominent design tradeoffs for such an application. read more

Actually, Tesla use synchronous electric motors, which uses both AC and DC. If the motor used just AC it would be a asynchronous induction motor, which is a unpredictable motor to use in vehicles due the slipping in the electromagnetic field when a voltage is induced in the rotor (The output-speed is slower than the rotation of the electromagnetic field. read more

Tesla uses 3-phase modulating inverter drivers, and the Tesla Roadster uses an AC induction motor. A DC brushless motor is the same thing, except instead of using laminations on the rotor, it uses magnets. read more

AC motors have lower peak efficiency (the best at about 92%) vs permanent magnet DC motors (up to 97%) but higher overall efficiency across the entire operating range, which is in uses such as vehicles. AC motor was invented by Nikola Tesla. The first proper controller/inverter was made in 1985 for industrial use and then in 1989 for cars (same guy). read more