A brief introduction to three-phase induction motors
Release date:
2025-08-05
Author:
Source:
Abstract
A three-phase asynchronous motor is a type of electric motor that operates by being simultaneously connected to a 380V three-phase AC power supply (with a phase difference of 120 degrees). Because the rotor of the three-phase asynchronous motor rotates in the same direction as, yet at a different speed from, the rotating magnetic field produced by the stator—resulting in a slip rate—it is called a three-phase asynchronous motor.
Motors come in many forms, but their operating principles are all based on the laws of electromagnetic induction and electromagnetic force. Therefore, the general principle behind their construction is to use appropriate magnetically conductive and electrically conductive materials to create magnetic circuits and electrical circuits that interact through electromagnetic induction, thereby generating electromagnetic power and achieving the goal of energy conversion.
The three-phase induction motor is an asynchronous motor. After current is applied to the stator, part of the magnetic flux passes through the short-circuited ring, inducing currents within it. These currents in the short-circuited ring oppose changes in the magnetic flux, creating a phase difference between the flux generated in the section with the ring and that in the section without it. This phase difference ultimately gives rise to a rotating magnetic field. Once energized and started, the rotor windings experience relative motion with respect to the rotating magnetic field, inducing electromotive forces and currents. In other words, there’s a relative speed between the rotating magnetic field and the rotor, and this interaction generates an electromagnetic torque, causing the rotor to turn—thus completing the energy conversion process.
Advantages: Compared to single-phase induction motors, three-phase induction motors have a simpler structure, are easier to manufacture, offer superior operational performance, and allow for significant savings in various materials, making them more affordable.
Recommended Reading
A brief introduction to three-phase induction motors
2025-08-05
The Importance and Recommendations for Completing the Motor Energy Efficiency Improvement Plan
2025-08-03
Motor efficiency and motor health conditions
2025-07-16