About Switched Reluctance Motor (SRM) | New Topic [2024]

In this note, we will learn about the Switched Reluctance Motor or SRM. Also its Construction of SRM, Working Principle of SRM and Characteristics as well. Welcome to Poly Notes Hub, a leading destination for Engineering Notes.

Author Name: Arun Paul.

What is Switched Reluctance Motor?

A switched reluctance motor (SRM) is an electric motor that uses the reluctance torque principle to operate. Unlike conventional motors, which employ permanent magnets or electromagnets to generate magnetic fields, an SRM depends on magnetic materials’ tendency to travel to areas with higher magnetic flux density. SRMs have a basic configuration consisting of a stator with salient poles and a rotor with no windings or permanent magnets. To generate torque, the motor successively energizes the stator windings. SRMs are noted for their high torque density, adaptability for high-speed applications, and durability in hostile conditions due to their simplified construction and fewer moving parts.

Construction of SRM

Below we describe the construction of Switched Reluctance Motor –

• Stator: Consists of laminated steel core with multiple salient poles.
• Rotor: Typically a simple steel structure with no windings or magnets.
• Windings: Wound around the stator poles, often with fewer turns compared to traditional motors.
• Rotor Position Sensors: Required for accurate commutation, typically optical or magnetic sensors.
• Control Electronics: Essential for precise timing of current pulses to the windings.
• No Permanent Magnets: SRMs rely solely on the reluctance torque principle for operation.
• Simple Structure: Fewer components compared to other motor types, leading to easier maintenance.

Working Principle of SRM

The Switched Reluctance Motor (SRM) works by taking advantage of magnetic materials’ tendency to gravitate towards places with higher magnetic flux density. Unlike traditional motors, it does not use permanent magnets or electromagnets on its rotor. Instead, it features a simple structure that includes a stator with salient poles and a rotor with no windings or permanent magnets. The motor creates torque by energizing the stator windings in a precise sequence as the rotor aligns with the changing magnetic field. This design produces a motor with a high torque density, adaptability for high-speed applications, and robustness in hostile conditions due to its simplified construction.

Advantages of SRM

Below we listed some advantages of Switched Reluctance Motor –

• It produces high amount of torque in comparison with the size.
• These motors operates efficiently at high speed as well.
• SRMs have a lower failure rate in hostile environments.
• Their less complicated design frequently results in cheaper production costs.

Disadvantages of SRM

Below we listed some disadvantages of Switched Reluctance Motor –

• Noise is high as compare to other motors.
• During operation, torque ripple may be seen in these types of motors.
• Partial loads may cause SRMs to operate less efficiently than when they are fully loaded.

Applications of SRM

Below we listed some applications of Switched Reluctance Motor –

• Used in Electric Vehicles.
• Used in HVAC System.
• Used in Industrial System.
• Used in Power Tools or Machine Tools as well.