An AC motor is called an induction motor because it operates on the principle of electromagnetic induction to generate motion. When an alternating current (AC) is applied to the stator windings of an induction motor, it produces a rotating magnetic field. This rotating magnetic field induces currents (eddy currents) in the rotor bars or conductors, which in turn create a second magnetic field. The interaction between the rotating magnetic field in the stator and the induced magnetic field in the rotor causes the rotor to rotate. This process of inducing currents in the rotor without direct electrical connection is known as electromagnetic induction, hence the name “induction motor.”
AC motor and induction motor are often used interchangeably, but strictly speaking, not all AC motors are induction motors. AC motors encompass a broader category that includes induction motors, synchronous motors, and others. However, in common usage, especially in industrial and commercial applications, the term “AC motor” is often synonymous with “induction motor” due to the widespread use of induction motors in various applications, from household appliances to industrial machinery.
The term “AC motor” is also known as an alternating current motor. This name reflects the type of electrical power (AC) that is used to operate the motor. AC motors are prevalent in electrical systems worldwide due to the widespread availability and ease of generation, transmission, and distribution of AC power.
The term “induction” in induction motor refers to the process of inducing currents in the rotor conductors through electromagnetic induction. As mentioned earlier, the stator windings of the motor induce a rotating magnetic field, which in turn induces currents in the rotor conductors without any physical connection between the stator and rotor windings. This principle distinguishes induction motors from other types of AC motors, such as synchronous motors, where the rotor rotates in synchronism with the rotating magnetic field of the stator.
An AC motor is called a brushless induction motor when it incorporates a design that eliminates the need for brushes and commutators, which are typically found in brushed motors. Brushless induction motors use electronic controllers to switch the stator windings in synchronization with the rotor position, thereby eliminating the physical contact and wear associated with brushes and commutators. This design enhances motor efficiency, reduces maintenance requirements, and extends the motor’s operational lifespan compared to brushed motors. Brushless induction motors are widely used in applications requiring high reliability, low maintenance, and precise control of motor speed and torque, such as in electric vehicles, HVAC systems, and industrial automation.