The stator core refers to the iron core parts used in the stator part of the motor. It is made of a series of laminated silicon steel plates to improve the efficiency and performance of the motor. The stator core is one of the most important parts of the motor, which directly affects the service life and performance of the motor.
Stator Core And Lamination
What Is The Stator Lamination?
Stator lamination and rotor lamination are two key components of an electric motor. Stator core is made up of thousands to hundreds of thousands of individual steel laminations. The process of manufacturing a stator core involves continuously placing laminations side-by-side.
The goal is to form a complete circular or ringed layer with the laminations. The process involves laying out each layer until the required length or number of layers is achieved.
The Role of the Stator Core
Support for Windings: Within the stator core, there place slots or cavities where the coil windings. These windings carry electrical current and create a magnetic field when energized. The stator core provides a stable and secure platform for these windings.
Magnetic Circuit: The stator core acts as a magnetic circuit that directs and amplifies the magnetic field generated by the windings. This magnetic field interacts with the rotor (in motors and generators) or the secondary winding (in transformers) to enable the conversion of electrical energy into mechanical energy or vice versa.
What is the Lamination?
Lamination refers to the process of creating the stator core by stacking and bonding thin steel sheets or laminated sheets. These solid metal laminations typically make for materials like silicon steel (electrical steel) or nickel and cobalt alloys.
Advantages Of Laminated Stator Cores
Minimizing Eddy Currents
The stator core comprises an electromagnetic field that produces a voltage, known as circulating current or eddy current.
In most cases, this type of current will result in decreased performance and power loss – caused by several factors like the density of magnetic flux and frequency of electromotive force (EMF).
Insulating the core with stator laminations reduces eddy currents. Layers of plates are placed on top of one another right in the middle to prevent eddy current flow. As a result, the reduced eddy current will mean that the stator core is able to keep its constant power and operate efficiently.
Reducing Hysteresis Loss
The stator core’s electromagnetic field also causes a degree of magnetization known as hysteresis. The process of magnetization and demagnetization creates a loop – the bigger it is, the higher the accumulated energy consumed to magnetize and demagnetize the core.
As the core generates heat from eddy current production, hysteresis loss occurs, costing large amounts of energy and power loss. Laminations minimize hysteresis loss to increase efficiency.
Here is where lamination plates come in to prevent such an incident with their narrow hysteresis loops which do the job of magnetize and demagnetize the stator core – by using less energy. Which also translates to more efficient equipment.
Improved Efficiency
Laminated stator cores result in higher machine efficiency. The reduction in eddy current losses means that a larger portion of the electrical energy convert into useful mechanical work or maintained as electrical output. Stator laminations offer significant benefits to help optimize engine performance.
Enhanced Performance
Laminated cores offer improved performance in terms of stability and precision. The laminations ensure uniformity in the core material properties and dimensions, leading to more predictable and reliable machine behavior.
Cooling the Stator Core
Solid metal pieces in stator cores may cause the stator core to overheat, increasing the risk of melting. Laminations reduce the amount of heat the core produces, keeping it cool enough to avoid melting.
Noise Reduction
Laminations also help in reducing noise, which is especially important in applications where quiet operation is essential, such as household appliances and electric vehicles.
Materials used in Lamination
At Motorneo, We commonly use electrical steel, amorphous alloys, nickel alloys, and cobalt alloys to manufacture electrical machine stators and rotor iron cores.
laminated Steel
Thin-gauge electrical steel is ideally suitable for applications with energy efficiency and high-performance requirements. This material offers excellent magnetic properties.
We commonly use electrical steel laminations ranging from 0.1 to 1 millimeter (mm). In addition, we use grades of electrical steel like M15, M19, M22, M27, M36, M45, etc.
Amorphous Alloys
Amorphous motor rotor and stator lamination stacks utilize 25 microns thickness 2605SA1, 2605HB1M, and1K101 iron-based amorphous alloy, and Metglas amorphous metal, ensuring higher saturation flux density while maintaining low core losses.
Nickel Alloys
In certain high-performance or specialized applications, nickel alloys may be used for motor laminations. These alloys provide exceptional magnetic properties and corrosion resistance, but they are generally more expensive than silicon steel.
Cobalt Alloys
Cobalt alloys have high tensile strength, excellent resistance to corrosion, heat, and wear and tear, and are a sought-after material for lamination. It is a fantastic choice for high-performance applications that require high flux densities and no saturation.
Capability for Lamination Process
Lamination Prorotypes
We produce these precise lamination prototypes using computer-controlled laser cutting machines or Wire-EDM. We can handle the most demanding motor lamination production needs within a turnaround time of 5-15 days.
Tool Design And Manufacture
We will design the corresponding stamping die according to the size, shape, and characteristics of the lamination. We use Wire-EDM and grinder technologies to fabricate mold. After all, the mold is crucial to the quality and burr control of the lamination.
Cutting and Stamping
The chosen silicon steel material is then cut into thin laminations or sheets, which our automatic feeders feed silicon steel strips into our stamping machine.
The high-speed punching machine and large press machine punch and drill electrical steel strips to create the desired laminated shape. The stamping process includes creating slots for windings and ensuring precise dimensions.
Stacking and Bonding
Our stamping laminations need to stack and bond to form the electric motor core. Technicians use rivets, splints, and glue to hold the stacked laminations pieces together. In addition, we use a material with glue for self-bonding.
Winding
The stator winding process involves winding insulated copper wire coils around the stator core to create electromagnetic fields that propel rotor motion. Our advanced winding techniques, such as automated winding machines, are employed to achieve consistent winding patterns and tension control.
Insulation
To prevent short circuits between laminations and windings, we employ injection molding and epoxy powder coating technology for motor lamination stacks insulation.
Quality Control
We have ISO9001:2008 international quality certification. These certifications reflect our strict quality control. Quality control measures include:
Dimensional Accuracy
We use CMM inspection and projector detector ensuring that the electric motor laminations meet the specified dimensions and tolerances.
Visual Inspection
Checking for any defects, such as cracks or irregularities in the laminations.
Magnetic Properties
Our advanced machine can test the magnetic properties to confirm they meet the required standards.
Bonding Integrity
We run tension tests to verify that the laminations are securely bonded and properly insulated.
How To Choose Lamination Thickness
We carefully choose the lamination thickness based on the specific requirements of the motor, generator, or transformer. For high-efficiency applications, we prefer to use thinner laminations. On the other hand, in applications where robustness and durability are paramount, we choose thicker laminations.
Stator Core Lamination in Different Applications
Motorneo customized motor stator stacks apply to electric vehicles, drones, elevators, pumps, fans, washing machines, electric drills, wind turbines, etc.
Looking to the high-performance electric motor iron core
We specialize in custom stator cores that will have a thickness of around 0.1 – 1 mm, with a length of 20 – 1250 mm which a wide range of applications, including industrial motors, automotive motors, elevator traction motors, diesel generators, wind and fire power generators, rail motors, transformers, and more.
Conclusion
The stator core is a vital component in the motor. Its quality and accuracy directly affect the performance and service life of the motor. Only by mastering the correct manufacturing methods and material selection can high-quality, high-performance motor products be produced.
FAQS
How do stator laminations reduce eddy currents?
Laminations minimize eddy currents by restricting the flow of these currents with their thin, insulated layers, reducing the core’s overall electrical resistance and heat generation.
Why is stator core lamination important?
Lamination is crucial because it significantly reduces eddy currents within the stator, which can cause excessive heat and energy loss, thereby improving the motor’s efficiency and longevity.
What Is The Difference Between The Stator And Rotor Laminations In An Electric Motor?
We know what rotor and stator laminate are, so let’s dive into the key differences between stator and rotor of electric motors.
Different Structures
The rotor is the moving part of the motor and usually consists of a magnetic core and windings, while the stator is the static part of the motor and usually consists of an iron core and coil windings.
Different Movement States
The rotor is the rotating part of the motor. It is generally driven to rotate by electromagnetic force and plays a role in converting energy in the motor. The stator is the immobile part of the motor, usually stationary, and forms a magnetic field through the coil windings to form the stator magnetic field of the motor.
Different Functions
The rotor is the rotating part and is the power source of the motor. The stator is the fixed part and plays the role of maintaining the magnetic field.