I'm confused - Does an induction motor used for an automobile convert DC battery power to AC? I'm under the impression that induction motors need AC power to run, so how can this quot;ACquot; motor use DC power to make AC? I'm aware that there are AC/DC inverters but wouldn't that make the whole system less efficient since it has to run through this extra device to make power?
All induction motors require AC to run. And in the case an electric car, the AC is produced by an inverter from the DC that comes from the batteries. And yes, it makes the whole system less efficient. Induction motors, and sometimes synchronous motors, are used because they're mechanically more reliable(no brushes or commutator to wear out) ,can have better speed control and speed monitoring than DC motors when used in conjunction with an variable-frequency inverter, and are lighter and cheaper than a DC motor of the same power rating. Before inverters that could handle the high power required by an electric car motor at a reasonable price were developed, the electric car with continuous throttle control would have been VERY inefficient or even impossible. But even with the loss of efficiency introduced by the inverter(something like 5-15% depending on the throttle setting, torque load, design of the inverter etc) it still beats the crap out of the efficiency of a gas engine, which is something like 20%.
There are no AC motors in an automobile. DC power is produced in an automobile by an alternator. An automobile alternator is a 3-phase, wound-field synchronous generator that converts mechanical power from the engine to AC power. The AC power is converted to DC power by s simple rectifier that is usually mounted inside the alternator.
