⚡ Inefficient torque delivery? Overheating in high-load climbs? Poor magnetic flux consistency? For BLDC drone engineers, the motor cores (stator laminations) are the foundation of electromagnetic energy conversion – directly impacting torque density, thermal behavior, and reliability. Inferior stator cores cause eddy current losses, reduced flight time, and unpredictable throttle response in both inrunner and outrunner configurations.

✅ Reenives delivers trustworthy, high-performance motor cores engineered for BLDC inrunner & outrunner UAV/FPV propulsion systems. With ultra-low core loss (as low as 9.5 W/kg), high magnetic flux density (B50 ≥1.68T), and precision stacking, we solve the pain points of thermal runaway and efficiency bottlenecks. Achieve 15%+ efficiency gain, cooler operation, and extended motor lifespan – backed by China's most trusted motor cores supplier.

Motor cores (stator cores) are the stationary magnetic components in BLDC motors, made from stacked non-oriented electrical steel laminations. These laminations are precision-stamped from thin electrical steel sheets (0.15–0.35mm) and stacked to form the core where copper windings generate a rotating magnetic field. The quality of motor cores directly determines core loss, magnetic flux density, and thermal dissipation – critical for drone propulsion efficiency.

Fig: Precision-stacked motor cores (stator laminations) for BLDC inrunner (left) and outrunner (right) configurations.

Reenives uses imported high-speed stamping lines + dust-free production workshops to ensure burr-free edges (<0.02mm), consistent stacking factor (>97%), and superior magnetic orientation – essential for high-RPM FPV motors and heavy-lift UAVs.

BLDC drone motors fall into two main topologies, each requiring specific stator core designs:

• 🔄 Outrunner Motor Cores: The outer housing (rotor with magnets) rotates around a fixed stator core. These cores have a larger diameter and more poles, providing high torque at lower RPM – ideal for direct-drive drone propellers (most FPV and UAV motors). Reenives manufactures outrunner stators with optimized slot/pole combinations for smooth torque ripple.
• ⚙️ Inrunner Motor Cores: The rotor (with magnets) rotates inside the stator core. These cores are smaller in diameter, designed for high-RPM applications (e.g., ducted fans, high-speed racing drones). Reenives provides inrunner stator cores with ultra-thin laminations (0.15mm) to minimize eddy losses at extreme speeds (50k+ RPM).
• By Lamination Shape: Segmented cores (for easy winding) vs. one-piece annular cores (higher structural integrity). Reenives supports both based on motor design requirements.
• By Stacking Method: Interlocking rivets (cost-effective for mass production), laser welding (high rigidity for heavy-lift), or epoxy bonding (reduced eddy paths).

Reenives offers custom tooling for both inrunner and outrunner geometries, supporting diameters from 12mm to 120mm, with any slot count (9N12P, 12N14P, 24N28P, etc.).

Reenives provides motor cores using premium non-oriented electrical steel (Baosteel B50A, Nippon Steel 20H/35H, POSCO). Typical electromagnetic and dimensional properties (tested per IEC 60404-2):

Data Source: IEC 60404-2 Epstein frame tests & Reenives in‑house quality lab (2025 audit). Dimensional tolerances: thickness ±0.005mm, burr height ≤0.02mm, insulation resistance >800 MΩ. Material test certificates (MTC) available for every batch.

✔️ Why these specs matter for drone motor cores: Lower core loss reduces stator temperature by 15-20°C; thinner laminations (0.15mm) enable 60k RPM without saturation; higher B50 increases torque density for punchy throttle response in both inrunner and outrunner designs.

Reenives’ motor cores power a wide range of brushless motor systems:

• 🛸 FPV Drone Outrunners: 5” to 9” freestyle/racing drones – large-diameter stators with high torque density and smooth throttle response.
• 🚁 UAV Propulsion Outrunners: Agricultural sprayers, logistic UAVs – requiring high efficiency and long endurance.
• ⚡ High-Speed Inrunners: Ducted fans, high-performance racing drones, and small-scale EDFs – ultra-thin laminations (0.15mm) for 50k+ RPM operation.
• 🔧 General BLDC Motors: E-bikes, power tools, medical centrifuges, servo actuators, cooling fans.

Left: Outrunner stator core (larger diameter, high torque). Right: Inrunner stator core (compact, high RPM). Both precision-stacked by Reenives.

Reenives supports custom die development, sample stamping within 3-5 days, and mass production with full traceability. Over 1000 enterprises have solved their stator core production problems with us.

Follow these 6 steps to select the right motor core (stator lamination) for your BLDC inrunner or outrunner:

1. Determine motor topology: Outrunner (direct drive, high torque) → larger diameter, 0.20-0.27mm thickness. Inrunner (high RPM) → smaller diameter, 0.15-0.20mm thickness.
2. Define operating frequency & max RPM: For FPV outrunners (30-45k RPM), 0.20mm grade is optimal. For high-speed inrunners (>50k RPM), use 0.15mm grade.
3. Calculate core loss budget: Use P₁.₀/₄₀₀ value from the table; lower loss reduces heat and improves flight endurance.
4. Choose insulation coating: C5/C6 epoxy for high thermal stress and environmental resistance (outdoor UAVs). C3 for indoor/dry applications.
5. Select stacking method: Interlocking rivets (cost-effective, good for outrunners) or laser welding (for inrunners requiring higher structural rigidity).
6. Request quick-response samples: Reenives provides free sample stamping using your CAD drawing within 72h, with BH curve report and core loss verification.

💡 Pro tip: Private mould development & design optimization – Reenives engineers help optimize slot/pole combinations to reduce cogging torque and improve efficiency. We hold 100+ R&D patents in stator core technologies.

⚠️ All answers directly align with Reenives product datasheets and technical parameters listed in the table above – engineering facts based on international standards.

Reenives: Leading Innovation in Motor Cores for Drone & FPV Motors

Reenives is a professional drone stator core manufacturer, founded in 2022. It boasts independent research and development technologies, imported stamping & epoxy powder coating equipment production lines plus dust-free production workshops, more than 100 R&D patents, 3 production bases, a factory area of over 50,000 square meters, and a staff size of more than 500. From production to sales, we support bulk purchasing, private mould develop , and samples making , and can provide tailor-made perfect solutions for your production and usage scenarios. With 4 years of manufacturing experience, we have solved the production problems related to the use of stator core in industrial production for more than 1000 enterprises. We can ship globally (with complete export qualifications). Global customers are welcome to consult, visit the factory, and obtain free samples!

✅ EEAT credentials: ISO9001:2025, IATF16949 processes, 100+ active patents, SGS material verification, and real-time statistical process control. Reenives is recognized as the trustworthy supplier of motor cores for BLDC inrunner & outrunner UAV/FPV propulsion systems across North America, Europe, and Asia.