AC Motors: Their Types and Advantages
An AC motor is a common type of electric motor that works on alternating current. As compared to the other effective motors used in daily industrial applications, AC motors produce mechanical energy from a single electrical input signal rather efficiently. Ac motors can be distinguished from other electrical motors particularly DC motors based on certain critical factors. The most important one of these is that this motor mostly relies on producing efficient mechanical energy by alternating the flow of current around its circuit.
Because of their low manufacturing costs, high affordability, ease of operation, they are used in a variety of industrial equipment and consumer products. They can be used in: Clocks, power tools, disk drives, washing machines and other domestic appliances, Audio turntables, fans etc.
AC Vs DC Motors
As mentioned before AC motors have some differences from other electrical motors especially DC motors. Some significant differences are:
- Like DC Motors AC motors do not include brushes. Which means that maintenance and replacement of parts are less needed, due to which they are expected to have longer average lives.
- A frequency drive control handles the output speed of many types of AC motor unlike DC motors.
- By using a more powerful current AC motors can generate higher torque than DC motors that is why they are more powerful.
- Dc motors are more efficient than AC motors because they make better use of their input energy.
Advantages of AC Motors
- Protects components at the receiving end and have low startup power demands.
- Starting current levels and acceleration can be controlled.
- They have longer life spans and high durability.
- They have the capabilities for multi-phase configurations.
Types of AC Motors
There are many several types of AC motors available in the market today, each differing slightly in their operations and outputs. When you are purchasing an AC motor keep these things in mind:
- Find brushless AC motors
- Look for Induction Ac motors
- Buy Synchronous AC motors
- Look for squirrel cage AC motors
- And shop for shaded-pole AC motors
Induction motor is a specific type of AC motor that includes an electrically charged rotor to create EMF around the stator, and thus creates the needed alternating current that the AC motor can then convert into mechanical energy. These can also be known as asynchronous motors because the rotor that is outside turns at a slower rate as compared to the frequency being applied to it.
It is a special type of AC motor in which the speed of the output rotor is directly aligned in sync with the alternating current being provided to it. It has additional electrical components fitted such as slip rings, through which is current is passed through the motors fixed and rotating parts. The speed of the rotor is directly proportional to the magnetic field of the stator.
Squirrel Cage Motors
Squirrel cage motors consists of a cylinder made from solid metal bars that conducts current through the rotor. The rotor bars involve no moving contacts within the withing the rotor mechanism itself, therefore they are more durable, less maintenance heavy, cheaper to produce and buy. These are a subtype of asynchronous AC induction motors.
Shaded Pole Motors
Shaded pole motors use an auxiliary rotor winding that is composed of either copper ring or bar, known as shading coil. They can operate at multiple speeds but produce a relatively small torque as compared to their torque on full speed. They are cheap to make and are more reliable due their simple construction. They are a subtype of single-phase squirrel cage motors.