Motovario motors How does a 3 Phase Motor Work? Three Phase Motors Motovario B14 Motor

How Does A 3 Phase Motor Work?

How does a 3 Phase Motor Work?

Wading into the ocean of technical jargon and electrical theory, one term often surfaces — Three Phase Motors. These unassuming components are the silent heroes behind industrial powerhouses, churning tirelessly to drive colossal machinery. As a part of 258 Engineering Supplies, we pride ourselves on our extensive knowledge of these components and boast an impressive stock of Three phase motors within the UK.

The forthcoming discourse will span the following areas:

  • An overview of Three Phase Motors
  • A dive into the realm of 3 Phase Power
  • The inner workings of a Three Phase Motor
  • An exploration of Motor Controllers
  • A final recap and conclusion

The Three-Phase Power and its Mysteries

the Alternating Current (AC)

Electricity, with its alternating current (AC) form, often exhibits a fickle and capricious demeanor. Much like a pendulum, it oscillates between positive and negative poles, birthing an oscillating magnetic field in the process. The beauty of AC lies in its easy manipulation and transformation, making it a choice pick for commercial and industrial applications.

Three-Phase Power in Industry and Commerce

Three-phase power represents a more refined and efficient sibling of AC. Imagine a waltzing trio instead of a lone dancer, with each partner stepping in at precise moments to maintain a continuous and balanced rhythm. This triadic power supply fuels the industrial world, delivering power with unwavering consistency.

Delving into the 3 Phase Motor

Introduction to the Three-Phase Motor as an AC Progeny

The world of motors is vast and diverse, with Three phase motors being a unique variant of the AC motor family. They are akin to well-oiled engines, propelling industrial machinery with their powerful torque.

Induction vs. Synchronous Motors: Spotting the Differences

In the realm of Three phase motors, two major subclasses exist: induction and synchronous motors. While both deliver power, they dance to different tunes. The induction motor relies on an induced magnetic field, while the synchronous motor marches in perfect synchronisation with the frequency of the supply current.

Dissecting a 3 Phase Motor: The Stator, Rotor, and Enclosure

A Three phase motor is more than what meets the eye. Beneath its sturdy enclosure, the stator and rotor exist in a perpetual state of magnetic dance. The stator, a static entity, creates a rotating magnetic field, while the rotor, the free-spirited counterpart, chases this rotating field, birthing rotation and hence, power.

Mechanism of a 3 Phase Motor

The Dance of Electromagnetic Induction

Like a conductor leading an orchestra, the principle of electromagnetic induction dictates the working of Three phase motors. When the stator’s rotating magnetic field cuts through the rotor’s coils, an opposing current gets induced, much like a timid response to a call.

The Role of the Rotating Magnetic Field (RMF)

The RMF, a fascinating phenomenon within three-phase induction motors, is the crux of motor operation. It’s akin to an unseen force, a magnetic ghost of sorts, nudging the rotor into action.

Induction of Opposing Magnetic Field: The Rotor’s Response

Upon the rotor’s brush with the RMF, it induces a current. This induced current birthes a magnetic field that opposes the stator’s magnetic field. It’s like a celestial chase, where the rotor perpetually follows the stator’s magnetic field, resulting in motor rotation.

Understanding the Phenomenon of Slip

“Slip” is not just about losing grip. In the world of three phase induction motors, it embodies a measure of how much the rotor lags behind the stator’s magnetic field. Altering the slip can control the motor speed, opening avenues for precise control.

Synchronous Motors: A Comparison

Contrary to induction motors, synchronous motors have their stator and rotor fields in locked alignment, moving in unison. It’s a different dance form altogether, one that requires precise tuning to the rhythm of the supply frequency.

Controllers: The Symphony Directors of 3-Phase Motors

The Connection between AC Frequency and Motor Speed

The speed of AC motors, including 3 phase variants, waltzes to the tune of supply frequency. Altering this frequency can control the tempo of the motor dance, modulating its speed as required.

The Role of Motor Controllers

Motor controllers are the conductors of the motor world. By managing the frequency input, they govern the motor speed, offering control over the wild dance of electrons within the motor.

Control of Speed via Slip Manipulation

While the motor controllers can control the supply frequency, it’s the slip that presents a more delicate tuning mechanism for motor speed. Tweaking the slip amounts to adjusting the lag between the rotor and stator’s fields, offering precise speed control.


This discourse journeyed through the intricacies of 3 phase motors, the pulsating heart of the industrial world. It delved into the nuances of three-phase power, explored the anatomy of a 3-phase motor, unraveled its working principle, and highlighted the role of motor controllers in managing its operation.


In the intricate world of electrical motors, Three phase motors claim a significant foothold. As this comprehensive guide unfolds, it becomes apparent how these motors are the linchpin in various industries. Their future holds immense potential, with advancements on the horizon promising to widen their application sphere.

We, at 258 Engineering Supplies, stand as one of the leading suppliers of three phase motors in the UK. Our commitment to quality and industry knowledge sets us apart. If you seek to delve deeper into the world of Three phase motors or need our expertise, do not hesitate to contact us.

Remember, it’s not just about understanding three phase motors but about appreciating the dance of power they orchestrate.

Rossi G Gearbox

Need Help Choosing?