The AC motor is best explained by starting with the fundamentals of alternating current. Alternating current is more economical to distribute over transmission lines because it can be "stepped up" in voltage using a transformer to reduce current and required wire size. This lowers both the first cost and operating cost. The voltage is "stepped down" again to the required voltage at the destination. Another big advantage is that AC motors are simpler to build and are thereby less expensive than DC motors, and require less maintenance.
Single-Phase AC
Three-Phase AC
