Views: 0 Author: Site Editor Publish Time: 2025-07-02 Origin: Site
Choosing the wrong core material can kill motor efficiency.BLDC motors need smart material selection for better power and lower loss.
This guide helps you pick the best core for your needs.You’ll learn which materials work best, why they matter, and how to compare them.
The stator core is where electricity turns into controlled motion.
It creates a path for magnetic flux, allowing interaction with the rotor’s permanent magnets.
This interaction generates torque—the turning force that moves the rotor.The core also holds the windings in place and adds structural strength.
It helps reduce core losses like eddy currents and hysteresis, which waste energy as heat.
The stator’s material affects how well the magnetic circuit works.
● Better materials mean less saturation, more torque, and higher efficiency.
● Poor choices lead to noise, overheating, and faster wear.
● Think of the core as the motor’s foundation—if it’s weak, the whole system suffers.
Choosing the right material for a BLDC stator core means understanding four core properties: magnetic permeability, electrical resistivity, core losses, and saturation magnetization. Each directly impacts how efficiently a motor performs and how long it lasts.
Magnetic permeability refers to how easily a material allows magnetic flux to pass through it.
● A higher permeability means the magnetic circuit is more effective, requiring less current to generate the same torque. This directly improves motor efficiency.High permeability = stronger torque at lower power.
● It's especially important in applications where efficiency and precision matter, such as medical tools, robotics, and compact electronics.
Materials like silicon steel, nanocrystalline alloys, and cobalt-iron offer excellent permeability.
This makes them ideal for stator cores in energy-conscious or space-constrained environments.
Material | Magnetic Permeability | Typical Application |
CRNGO Steel | Moderate | Appliances, general motors |
Amorphous Alloy | Very High | EVs, drones, high-efficiency use |
Nanocrystalline Core | Ultra High | Aerospace, medical, robotics |
Electrical resistivity determines how well a material resists the formation of eddy currents—tiny loops of induced current within the core that generate heat and cause energy loss.
● High resistivity = lower eddy current loss.
● This is crucial at high operating frequencies where magnetic switching happens quickly.
When materials have low resistivity, they become less efficient at high speeds and heat up faster.
That shortens motor lifespan and raises energy consumption.For this reason, amorphous metals and high-resistivity silicon steels are often used in high-speed BLDC motors.
Property | Low Resistivity | High Resistivity |
Heat Generation | High | Low |
Efficiency | Lower at high frequency | Higher at high frequency |
Material Types | CRNGO, GOES | Amorphous, nanocrystalline |
Core losses are the two main sources of energy waste in stator cores:
Eddy current loss and hysteresis loss.
● Eddy current loss: These circular currents flow within the metal core, creating heat.
Laminating the core with thin insulated layers helps stop them.
● Thinner laminations = less eddy loss.Hysteresis loss: Happens when the magnetic domains inside the material resist changing direction.
This occurs every time the field switches polarity—which is constant in BLDC motors.
Materials with low coercivity (resistance to magnetization) help reduce this.
Both losses increase with frequency. So high-speed applications like drones and e-bikes require materials designed for low total core loss.
Loss Type | Source | Reduction Method |
Eddy Current | Conductive loops in metal | Lamination, high resistivity material |
Hysteresis | Magnetic domain resistance | Low coercivity materials, thermal treatment |
Saturation magnetization is the maximum amount of magnetic flux a material can handle.
● Once saturated, adding more current doesn’t increase torque—it just causes heat buildup and waste.Higher saturation = more torque at high current levels.
● Useful in high-power or high-load applications like EV motors or industrial robots.
When designing for high torque output, pick materials with a high saturation point.
Cobalt-iron alloys, for example, handle high flux densities without overheating.Avoiding early saturation helps maintain motor efficiency, protect the core from thermal degradation, and extend system life.
Material Type | Saturation Level | Best For |
CRNGO Steel | Medium | Household appliances |
Cobalt-Iron Alloy | Very High | EVs, robotics, servo motors |
Nanocrystalline | Moderate-High | High-frequency precision systems |
● Standard material in many motors
● Balanced cost and performance
● Works across various motor sizes and speeds
● Lower core loss in one direction
● Ideal for aligned magnetic fields (less used in BLDC)
● Very low core loss due to disordered atomic structure
● Expensive and brittle, used in high-efficiency applications
● Ultra-low losses at high frequencies
● Great for aerospace, medical, or high-speed tools
● Extremely high magnetic saturation
● Expensive but perfect for compact and fast motors
Material Type | Loss Level | Cost | Use Case |
CRNGO Steel | Medium | Low | General-purpose BLDC motors |
Amorphous Alloy | Very Low | High | High-efficiency, small-form motors |
Cobalt-Iron Alloy | Low | Very High | Aerospace, servo, compact high-torque |
Nanocrystalline | Very Low | High | High-frequency, premium motor designs |
When designing smaller BLDC motors, size constraints limit the available core volume.
Yet, these motors still require high torque output. That’s where high magnetic saturation materials come in.
They allow stronger magnetic flux within a smaller form factor—resulting in better power density.In compact devices like drones, medical tools, and wearables, every millimeter counts.
However, smaller stator cores also have less surface area for heat dissipation.
This makes low-loss core materials essential to prevent overheating in confined spaces.
● Look for materials that offer high flux density and minimal core losses.
● Avoid materials that saturate quickly under moderate loads—they limit torque performance.
As the motor’s speed increases, the magnetic field in the stator reverses more rapidly.
This causes greater hysteresis and eddy current losses, especially if the material can’t handle high-frequency switching.
At high RPM, even minor inefficiencies multiply quickly into serious energy loss.To maintain performance at high speed:
● Choose materials with low coercivity (resist magnetization reversal loss).
● Prioritize high electrical resistivity to reduce eddy currents.
These materials help motors stay cool and efficient even under demanding operating cycles.
Applications include electric vehicles, robotics, and industrial automation.
Frequency Range | Material Recommendation |
Low to Medium | CRNGO Steel |
Medium to High | GOES, High-Grade Silicon Steel |
High & Dynamic | Nanocrystalline or Amorphous Alloy |
Thin laminations (0.2–0.5 mm) reduce eddy current loss.
Thinner means better performance—but also higher cost.Use thinner laminations for high-efficiency or high-speed motors.
Each lamination is coated to prevent current leaks.
● Options include:Organic: Flexible, good for moderate heat
● Inorganic: Durable in harsh environments
● Hybrid: Balanced for broad use
Coating Type | Heat Resistance | Cost | Best Use Case |
Organic | Medium | Low | Home appliances, HVAC |
Inorganic | High | Medium | Industrial, high-temp motors |
Hybrid | Balanced | Medium | Robotics, EVs, general use |
EV motors demand torque and heat resistance.
● Recommended: Cobalt-iron or high-grade silicon steel
● Built for stop-and-go torque and long-range efficiency
Lightweight is key. High efficiency matters too.
● Recommended: Amorphous or nanocrystalline
● Offers high performance in small, agile form factors
Cost and reliability are priorities.
● Recommended: CRNGO steel
● Balanced for everyday use and easy to source
Quiet operation, long life, and heat stability are critical.
● Recommended: High-resistivity, coated alloys
● Often custom-designed for specific devices
If you only focus on price, you may choose a material that wastes power.
Even 2–3% extra core loss adds up over time in large-scale production.
Oversized cores add bulk without benefit.
Saturated cores can’t carry more magnetic flux—resulting in heating and loss.
Choose the right size and balance.
Not all materials cut or stamp well.
Some are brittle, others damage tools.
Test early to make sure the material works on your production line.
The right stator material boosts motor power and cuts energy loss.Choose based on performance, cost, and your motor's job.Smart material selection builds stronger, longer-lasting, high-efficiency BLDC motors.
A: Nanocrystalline or amorphous alloys offer ultra-low core loss and high efficiency at high frequencies.
A: It's possible but uncommon. It complicates manufacturing and may reduce magnetic uniformity.
A: Thinner laminations reduce eddy currents, improving efficiency—especially at high speeds.
A: Not ideal. They’re expensive and hard to process, better for high-end or compact designs.
A: Inorganic or hybrid coatings resist moisture, corrosion, and chemical breakdown effectively.
