The three phase motor stands as a cornerstone of modern industrial power, providing the mechanical force that drives countless machines, pumps, and fans. Its operation is elegantly grounded in the principles of electromagnetism and the unique characteristics of a three-phase alternating current supply. Unlike single-phase motors, a three phase motor does not require auxiliary components like start capacitors to initiate rotation, granting it a robust and self-starting capability. The fundamental action occurs within the motor's stator, the stationary outer shell. Inside the stator core, windings are arranged symmetrically and connected to the three separate AC power lines. These windings are physically offset from one another by one hundred and twenty electrical degrees, mirroring the phase displacement of the incoming three-phase voltage.

When energized, this specific arrangement of windings carrying three-phase currents produces a profound effect: a magnetic field that rotates smoothly at a constant speed. This phenomenon is the heart of a three phase motor's operation. The speed of this rotating magnetic field, known as synchronous speed, is determined by the frequency of the power supply and the number of poles designed into the stator windings. Within this rotating field sits the rotor, the moving part of the motor. In the most common type, the squirrel-cage induction three phase motor, the rotor is constructed from laminated steel sheets with embedded conductive bars short-circuited at both ends by rings. As the stator's magnetic field sweeps past these rotor bars, it induces an electrical current within them.

It is important to note that the rotor in a standard induction three phase motor always turns at a speed slightly slower than the synchronous speed of the stator field. This difference, called slip, is essential because it allows for the continuous induction of current in the rotor conductors. The construction is notably durable; the squirrel-cage rotor has no physical electrical connections to the stator, eliminating the need for brushes and commutators. This results in a three phase motor that is reliable, requires minimal maintenance, and handles substantial mechanical loads efficiently. The generation of this rotating magnetic field is the critical, inherent advantage that makes the three phase induction motor a dominant choice for fixed-speed industrial applications worldwide.