An AC motor is a type of electric motor that’s driven by an alternating current. AC motors are found in a variety of industrial equipment applications and offer an efficient method of producing mechanical energy from an electrical input signal. 

This type of motor is different to the more familiar DC motors, which function through a direct current.

They can be distinguished by various criteria such as input power, speed control, and performance. Unlike DC motors, these motors don’t feature brushes which makes them much less prone to needing repairs and means they have a longer life expectancy.

These motors are used in a diverse range of industrial applications and familiar consumer products due to their durable nature, ease of operation and general affordability. It’s important to note that there are various types of AC motors and you must be aware of the differences to ensure you choose the right one to suit the needs of your equipment.

In this guide, we take a look at the various types of AC motors and the differences between them.

 

Induction motors

An induction motor, also called an asynchronous motor, is one of the most common types of AC electric motor.

In this design, the required current is produced through electromagnetic induction from the rotating magnetic field as a result of the stator winding. There are two main components to an AC motor: the stator and the rotor. Within the category of AC induction motors, we can divide them further:

Single-phase motors

These motors have one stator and don’t feature the rotating magnetic field that other types of induction motors have. They are the preferred motor for domestic, commercial applications as well as in industrial equipment including:

• Pumps
• Compressors
• Small fans
• Mixers
• Drilling machines.

 

 

Polyphase motors

Polyphase motors can be two or three phase motors. They are similar to single-phase motors in terms of functionality, but operate with rotating magnetic fields.The rotating magnetic field is created by a two or three phase current that flows through groups of coils to produce torque. They are used in operations that require high power, for example in industrial applications such as:

• Compressors
• Irrigation pumps
• Hydraulic pumps
• Lifts
• Cranes
• Hoists
• Large exhaust fans
• Oil extracting mills.

 

 

Squirrel cage induction motor

This is a type of three-phase induction motor and gets its name from the rotor inside it which resembles a squirrel cage. This rotor features a surface of highly conductive metal. When the alternating current goes through the stator, the rotating magnetic field is generated. They are often found in equipment such as: 

• Centrifugal pumps
• Industrial drives (used to run conveyor belts)
• Large blowers and fans
• Machine tools
• Lathes and other turning equipment

 

 

Synchronous motors

Another common type of AC motor is called a synchronous motor. These motors operate at a speed which is in sync with the frequency of the supply current. As a result of the steady state of the motor, the rotation of the stator synchronises with the supply current meaning the rotation period of the shaft is equal to the number of AC cycles.

Syncronised rotors don’t depend on the induction current to function, instead multiphase AC electromagnets found on the stator produce a rotating magnetic field. One advantage of this type of motor is that its magnetic field can be produced by the direct current in the field winding. This means the stator windings can provide a power component of current that aligns with the applied stator voltage.

 

 

This type of motor is used in applications that require constant and precise speed. Some typical industrial applications of synchronous motors include:

• Blowers
• DC generators
• Centrifugal pumps
• Compressors
• Rubber and paper mills.

 

Discover AC motors and spare parts with Preferred Spares

Preferred Spares is a leading supplier of industrial automation equipment and spare parts serving the UAE.

Whether you’re looking for a new AC motor for an industrial application or you need parts for AC motor repair, Preferred Spares delivers a range of quality, robust solutions to meet the needs of diverse clients.

 

For all your spare parts needs or for advice on implementing AC motor solutions, visit the Preferred Spares website or contact us today.