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THE IMPORTANCE OF PROPER LAMINATION
IN ROTOR AND STATOR CORES

Stator core laminations are essential components in electric induction motors, playing a crucial role in optimizing performance and efficiency. These thin sheets of steel, typically made from electrical or silicon steel, are coated with an insulating material and precisely stacked to create a circular lamination stack surrounding the stator winding. The primary function of a stator core is to convert electrical energy into mechanical energy by generating a magnetic field that interacts with the rotating shaft, producing rotational force.

STATOR CORES LAMINATION

Stator cores are laminated to address two significant challenges: eddy current loss and hysteresis loss. Eddy currents are induced in the stator core when exposed to a variable magnetic field due to alternating current flowing through the windings. These circulating currents cause power loss and excessive heating in the motor. By laminating the stator core, these eddy currents are significantly reduced. Laminations also minimize hysteresis loss, which occurs when the magnetic domains within the steel core realign constantly in response to changes in the magnetic field, resulting in heat dissipation. Laminations provide a smooth, consistent surface for rotation, reducing hysteresis loss and improving energy conversion efficiency.

 

Rotor for electric motor, exploded view isolated on white backgr

MATERIALS USED FOR STATOR LAMINATIONS

Silicon steel is commonly used for stator laminations due to its excellent magnetic properties. It offers low core losses while maintaining high magnetic permeability, making it ideal for high-performance applications that require energy efficiency. In specialized applications demanding exceptional magnetic properties, corrosion resistance, or high flux densities, alternative  materials like nickel or cobalt alloys may be used.

ROLE OF STATOR CORE LAMINATIONS IN INDUCTION MOTORS

Stator core laminations play a critical role in the operation of induction motors, contributing to several aspects of motor performance and efficiency.

COOLING FUNCTION

Proper cooling is essential to maintain optimal motor performance and prevent damage from overheating. Stator core laminations facilitate heat flow management within the motor by acting as pathways for cooling gases like hydrogen or air, allowing efficient heat transfer away from critical components.

IMPROVING EFFICIENCY AND PERFORMANCE

Stator core laminations significantly contribute to the overall efficiency and performance of induction motors. By reducing power loss from eddy currents and hysteresis, a larger portion of electrical energy is converted into useful mechanical work or retained as electrical output. The smooth surface of the stator laminations minimizes hysteresis loss, ensuring efficient rotational force generation. Additionally, laminated cores provide uniform material properties and dimensions, enhancing motor stability and precision during operation.

BENEFITS OF STATOR CORE LAMINATIONS

consumo-de-energia (2)

REDUCED POWER LOSS

Laminations reduce eddy currents and hysteresis loss, leading to greater energy efficiency.

mejora-del-rendimiento (1)

IMPROVED MECHANICAL PERFORMANCE 

The smooth surface minimizes hysteresis loss, enabling efficient energy conversion.

continuidad (1)

GREATER STABILITY AND PRECISION

Uniform material properties and dimensions ensure consistent performance.

ROTOR LAMINATIONS

Rotor laminations are also made from laminated sheets of metal alloy, but they are more complex in design. While the stator generates a magnetic field, the rotor’s primary task is to respond to that magnetic field and generate rotational movement. Rotor lamination stacks are typically made from thicker metal sheets that are easily magnetized and demagnetized. The stacks consist of several layers of steel sheets cut into precise shapes to create the rotor’s electromagnetic field when paired with the stator. The rotor is usually the motor’s moving component, with its central shaft passing through the stator’s center. Without the rotor, the motor could not generate power, as the interaction between the stator’s magnetic field and the rotor’s current creates the rotational motion.

KEY DIFFERENCES BETWEEN ROTOR AND STATOR LAMINATIONS

  • Application in the Motor: The stator core is a stationary component that creates a magnetic field, while the rotor is the rotating component that responds to that magnetic field.
  • Thickness: Stator lamination stacks are made from thin metal sheets, typically only a few tenths of a millimeter thick. In contrast, rotor laminations are thicker, often several times the thickness of stator laminations.
  • Materials: Stator cores typically use low-carbon steel alloys, which are economical, easy to work with, and offer high magnetic permeability. Rotor laminations require thicker materials like nickel or cobalt, which have a higher magnetic saturation point than low-carbon steel.
  • Function: Stator laminations reduce power loss, vibration, and noise through their stacked design, which helps reduce eddy currents and improve magnetic flow. In contrast, rotor laminations respond to the magnetic field generated by the stator, creating the mechanical rotation needed for power generation. This is achieved through the rotor’s complex shape and precise arrangement of its laminated sheets.
  • Shape: Stator laminations typically have an annular shape surrounding the rotor, while the rotor is a simple cylinder with or without external fins.
Sheet metal parts used for rotor package manufacturing, 3d rende
Sheet metal part used for stator manufacturing
Lamination for rotor 3D rendering
Lamination for stator 3D rendering

COMMON APPLICATIONS OF ROTOR AND STATOR LAMINATIONS

Electric motors are suitable for various applications, and laminated cores are essential. Common applications include industrial equipment and machinery, HVAC systems, electric vehicles, power tools, household appliances, and renewable energy systems such as wind turbines, where rotor laminations are critical for converting wind energy into electrical energy.

ADVANCES MANUFACTURING
Lamination manufacturing technology has evolved significantly, driven by the demand for compact stacks and the reduction of noise and vibration. Geometric precision in stacks has become increasingly important, emphasizing the need for consistent mechanical properties. Various stacking methodologies have been developed to maintain electrical insulation between laminations, focusing on cost-effectiveness for highvolume production. Traction motor laminations produced in large volumes are typically cut and shaped from sheet metal in stamping machines equipped with progressive die sets.

Thinner gauges and more complex lamination designs require more stages in die sets, necessitating longer presses. To form rotor or stator cores, the resulting laminations can be loosely stacked, interlocked, welded, or bonded with adhesives, or a combination of these methods. In-press interlocking, often supplemented with welding, is the most common method due to its balance of tolerance and cost. However, advanced bonding techniques like adhesive bonding are gaining popularity due to their potential to reduce eddy current losses.

FUTURE TRENDS

The trend toward thinner laminations with lower losses and higher strength is expected to continue. Innovations in bonding technologies and materials will likely improve the performance and efficiency of electric motors. Laminations with thicknesses as low as 0.2 mm or less are expected to be routinely used in large-scale commercial production. Stress-relief annealing is also expected to become more widespread to eliminate the impact of the stamping process on magnetic properties.

As a conclusion, we can say rotor and stator laminations are critical for optimizing the performance and efficiency of electric motors. Advances in materials, manufacturing processes, and bonding technologies continue to drive improvements in motor design, contributing to the broader adoption of electric vehicles and other electromechanical systems

RELATED SOLUTIONS

HIGH SPEED PRESS FOR ROTOR AND
STATOR LAMINATION

Fagor Arrasate's High-Speed Presses are designed to offer exceptional productivity and unparalleled precision in every operation. Every feature of our machines has been developed to ensure that lamination processes, not only meet, but exceed the most stringent quality standards of the industry.

More information

SLITTING LINE FOR ELECTRICAL
STEEL

Our slitting line for electrical steel is designed to meet high standards of quality and precision . This line incorporates advanced technology that maximizes efficiency and accuracy, ensuring the preservation of vital magnetic properties and minimizing energy losses.

More information

THE IMPORTANCE OF PROPER LAMINATION
IN ROTOR AND STATOR CORES

Stator core laminations are essential components in electric induction motors, playing a crucial role in optimizing performance and efficiency. These thin sheets of steel, typically made from electrical or silicon steel, are coated with an insulating material and precisely stacked to create a circular lamination stack surrounding the stator winding. The primary function of a stator core is to convert electrical energy into mechanical energy by generating a magnetic field that interacts with the rotating shaft, producing rotational force.

STATOR CORES LAMINATION

Stator cores are laminated to address two significant challenges: eddy current loss and hysteresis loss. Eddy currents are induced in the stator core when exposed to a variable magnetic field due to alternating current flowing through the windings. These circulating currents cause power loss and excessive heating in the motor. By laminating the stator core, these eddy currents are significantly reduced. Laminations also minimize hysteresis loss, which occurs when the magnetic domains within the steel core realign constantly in response to changes in the magnetic field, resulting in heat dissipation. Laminations provide a smooth, consistent surface for rotation, reducing hysteresis loss and improving energy conversion efficiency.

 

Rotor for electric motor, exploded view isolated on white backgr

MATERIALS USED FOR STATOR LAMINATIONS

Silicon steel is commonly used for stator laminations due to its excellent magnetic properties. It offers low core losses while maintaining high magnetic permeability, making it ideal for high-performance applications that require energy efficiency. In specialized applications demanding exceptional magnetic properties, corrosion resistance, or high flux densities, alternative  materials like nickel or cobalt alloys may be used.

ROLE OF STATOR CORE LAMINATIONS IN INDUCTION MOTORS

Stator core laminations play a critical role in the operation of induction motors, contributing to several aspects of motor performance and efficiency.

COOLING FUNCTION

Proper cooling is essential to maintain optimal motor performance and prevent damage from overheating. Stator core laminations facilitate heat flow management within the motor by acting as pathways for cooling gases like hydrogen or air, allowing efficient heat transfer away from critical components.

IMPROVING EFFICIENCY AND PERFORMANCE

Stator core laminations significantly contribute to the overall efficiency and performance of induction motors. By reducing power loss from eddy currents and hysteresis, a larger portion of electrical energy is converted into useful mechanical work or retained as electrical output. The smooth surface of the stator laminations minimizes hysteresis loss, ensuring efficient rotational force generation. Additionally, laminated cores provide uniform material properties and dimensions, enhancing motor stability and precision during operation.

BENEFITS OF STATOR CORE LAMINATIONS

consumo-de-energia (2)

REDUCED POWER LOSS

Laminations reduce eddy currents and hysteresis loss, leading to greater energy efficiency.

mejora-del-rendimiento (1)

IMPROVED MECHANICAL PERFORMANCE 

The smooth surface minimizes hysteresis loss, enabling efficient energy conversion.

continuidad (1)

GREATER STABILITY AND PRECISION

Uniform material properties and dimensions ensure consistent performance.

ROTOR LAMINATIONS

Rotor laminations are also made from laminated sheets of metal alloy, but they are more complex in design. While the stator generates a magnetic field, the rotor’s primary task is to respond to that magnetic field and generate rotational movement. Rotor lamination stacks are typically made from thicker metal sheets that are easily magnetized and demagnetized. The stacks consist of several layers of steel sheets cut into precise shapes to create the rotor’s electromagnetic field when paired with the stator. The rotor is usually the motor’s moving component, with its central shaft passing through the stator’s center. Without the rotor, the motor could not generate power, as the interaction between the stator’s magnetic field and the rotor’s current creates the rotational motion.

KEY DIFFERENCES BETWEEN ROTOR AND STATOR LAMINATIONS

  • Application in the Motor: The stator core is a stationary component that creates a magnetic field, while the rotor is the rotating component that responds to that magnetic field.
  • Thickness: Stator lamination stacks are made from thin metal sheets, typically only a few tenths of a millimeter thick. In contrast, rotor laminations are thicker, often several times the thickness of stator laminations.
  • Materials: Stator cores typically use low-carbon steel alloys, which are economical, easy to work with, and offer high magnetic permeability. Rotor laminations require thicker materials like nickel or cobalt, which have a higher magnetic saturation point than low-carbon steel.
  • Function: Stator laminations reduce power loss, vibration, and noise through their stacked design, which helps reduce eddy currents and improve magnetic flow. In contrast, rotor laminations respond to the magnetic field generated by the stator, creating the mechanical rotation needed for power generation. This is achieved through the rotor’s complex shape and precise arrangement of its laminated sheets.
  • Shape: Stator laminations typically have an annular shape surrounding the rotor, while the rotor is a simple cylinder with or without external fins.
Sheet metal parts used for rotor package manufacturing, 3d rende
Sheet metal part used for stator manufacturing
Lamination for rotor 3D rendering
Lamination for stator 3D rendering

COMMON APPLICATIONS OF ROTOR AND STATOR LAMINATIONS

Electric motors are suitable for various applications, and laminated cores are essential. Common applications include industrial equipment and machinery, HVAC systems, electric vehicles, power tools, household appliances, and renewable energy systems such as wind turbines, where rotor laminations are critical for converting wind energy into electrical energy.

ADVANCES MANUFACTURING
Lamination manufacturing technology has evolved significantly, driven by the demand for compact stacks and the reduction of noise and vibration. Geometric precision in stacks has become increasingly important, emphasizing the need for consistent mechanical properties. Various stacking methodologies have been developed to maintain electrical insulation between laminations, focusing on cost-effectiveness for highvolume production. Traction motor laminations produced in large volumes are typically cut and shaped from sheet metal in stamping machines equipped with progressive die sets.

Thinner gauges and more complex lamination designs require more stages in die sets, necessitating longer presses. To form rotor or stator cores, the resulting laminations can be loosely stacked, interlocked, welded, or bonded with adhesives, or a combination of these methods. In-press interlocking, often supplemented with welding, is the most common method due to its balance of tolerance and cost. However, advanced bonding techniques like adhesive bonding are gaining popularity due to their potential to reduce eddy current losses.

FUTURE TRENDS

The trend toward thinner laminations with lower losses and higher strength is expected to continue. Innovations in bonding technologies and materials will likely improve the performance and efficiency of electric motors. Laminations with thicknesses as low as 0.2 mm or less are expected to be routinely used in large-scale commercial production. Stress-relief annealing is also expected to become more widespread to eliminate the impact of the stamping process on magnetic properties.

As a conclusion, we can say rotor and stator laminations are critical for optimizing the performance and efficiency of electric motors. Advances in materials, manufacturing processes, and bonding technologies continue to drive improvements in motor design, contributing to the broader adoption of electric vehicles and other electromechanical systems

RELATED SOLUTIONS

HIGH SPEED PRESS FOR ROTOR AND
STATOR LAMINATION

Fagor Arrasate's High-Speed Presses are designed to offer exceptional productivity and unparalleled precision in every operation. Every feature of our machines has been developed to ensure that lamination processes, not only meet, but exceed the most stringent quality standards of the industry.

More information

SLITTING LINE FOR ELECTRICAL
STEEL

Our slitting line for electrical steel is designed to meet high standards of quality and precision . This line incorporates advanced technology that maximizes efficiency and accuracy, ensuring the preservation of vital magnetic properties and minimizing energy losses.

More information

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