AC Motors
AC Motors

AC Motors

This paper is about AC motors; definitions, history, how it works, and advantages and disadvantages.

Definition : The motor that converts the alternating current into mechanical power by using an electromagnetic induction. This AC Motors are driven by an alternating current. The stator and the rotor are the two most important parts of the AC motors. Stator is the stationary part of the motor, and the rotor is the rotating part of the motor. Besides, AC motor may be single phase or three phase.

The three phase AC motors are mostly applied in the industry for bulk power conversion from electrical to mechanical. For small power conversion, the single phase AC motors are mostly used. The single phase AC motor is nearly small in size. And it provides a variety of services in the home, office, business concerns, factories, etc. Almost all the domestic appliances such as refrigerators, fans, washing machine, hair dryers, mixers, etc., use single phase AC motor.

History of AC Motors

In this paragraph, Nikola Tesla invented the first AC Induction Motor in 1888. Introducing a more reliable and efficient motor than the DC motor. However, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor. Because of its efficient and economical means of controlling speed accurately. Over time, AC Drive technology eventually transformed into an inexpensive. And reliable competitor to the traditional DC control. Now, an AC Controller is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

The biggest advantage is their sheer simplicity. They have only one moving part, the rotor, which makes them low-cost, quiet, long-lasting. And relatively trouble free. DC motors, by contrast, have a commutator and carbon brushes that wear out and need replacing from time to time. The friction between the brushes and the commutator also makes DC motors relatively noisy. (and sometimes even quite smelly).

AC Motors
AC Motors

How AC Motors Work

The fundamental operation of an AC Motor relies on the principles of magnetism. The simple AC Motor contains a coil of wire and two fixed magnets surrounding a shaft. When an electric (AC) charge is applied to the coil of wire, it becomes an electromagnet, generating a magnetic field. Simply described, when the magnets interact, the shaft and the coil of wires begin to rotate, operating the motor.

AC Motors drawing
AC Motors drawing

Advantages and Disadvantages of AC Motor

Firstly, Advantages

– Low Cost

– Long Lifespan

– High-Efficiency and Reliability

– Simple Construction

– High Starting Torque (Induction)

– No Slip(Synchronous)


– Frequency Causes Rotation Slips (Induction)

– Starting Switch Needed (Induction)


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