An outer slot stator core refers to a stator lamination design where the Field Excitation Coil (FEC) slots are positioned on the outer circumference of the stator core. In permanent magnet flux switching machines (PMFSM), the arrangement of FEC slots—inner FEC slot, outer FEC slot, or toroidal FEC slot—significantly impacts motor performance. Research on various slot structures of FEC demonstrates that the outer slot configuration offers distinct advantages for field excitation efficiency and magnetic flux distribution.

Reenives manufactures high-quality outer slot stator cores using non-grain oriented silicon steel (0.20mm/0.35mm) with advanced C5 epoxy powder coating — ensuring low core loss (≤8.2 W/kg @400Hz) and high thermal stability for sustained drone and PMFSM operation.

Reenives offers outer slot stator cores across multiple slot/pole configurations and material grades to meet diverse application requirements:

• By Slot Arrangement: Outer FEC slot (optimized for specific field excitation characteristics), inner FEC slot, and toroidal FEC slot.
• By Slot/Pole Config: 9N12P (high RPM racing), 12N14P (balanced torque/speed for UAVs), 18N20P (high torque density), 24N28P (heavy-lift / eVTOL).
• By Material Thickness: 0.15mm (ultra-high RPM), 0.20mm (standard high-frequency UAV), 0.27mm, and 0.35mm (general industrial).
• By Insulation Coating: C5 epoxy powder coating (Class H, 180°C) with >4000V dielectric strength.
• By Stacking Method: Interlocking self-bonding, laser welding, or epoxy bonding.

💡 Reenives specialty: private mould development for custom outer slot stator geometries — including optimized outer FEC slot profiles for specific PMFSM and drone motor applications.

All parameters validated by Reenives R&D center (ISO 9001:2025 certified) and third-party testing per IEC 60404-2, ASTM A912. Slot structure research conducted on PMFSM machines with various FEC slot arrangements, including outer slot configurations.

📐 Data source: Reenives in-house quality lab, 2025–2026. CMQIC Test Report #MQ-25-112. No-load study of PMFSM with various slot structures of FEC. Full batch traceability and material certificates available.

Reenives outer slot stator cores power critical applications across multiple sectors:

• FPV Racing & Cinematic Drones: 2207, 2306, 2507 outer slot stators with instant throttle response and reduced cogging torque.
• Commercial UAVs & eVTOL: 12N14P / 18N20P outer slot stators for 15-30kg payload with optimized field excitation efficiency.
• Permanent Magnet Flux Switching Machines (PMFSM): Outer FEC slot configurations deliver distinct advantages for field excitation efficiency and magnetic flux distribution.
• Industrial BLDC Actuators & Servos: Precision outer slot cores for cogging-free torque in robotics and automation.
• Agricultural Spraying Drones: High-torque outer slot stators with C5 epoxy coating offering 500h+ salt spray resistance.

1. Define motor topology and slot arrangement: For PMFSM and flux switching machines, determine whether outer FEC slot, inner FEC slot, or toroidal FEC slot best suits your application.
2. Choose lamination material thickness: 0.15mm for ultra-high RPM >50,000; 0.20mm for standard high-frequency UAV; 0.35mm for robust industrial motors.
3. Select slot/pole combination: 9N12P for high RPM racing, 12N14P for balanced torque/speed (most common for UAVs), 18N20P for high torque density.
4. Specify insulation and environmental protection: C5 epoxy coating for outdoor UAVs; oil-compatible coating for EV/hybrid applications.
5. Request samples and validation: Reenives delivers first-article inspection reports (FAI) and material certificates. Prototype outer slot stator samples ready in 7-10 days after design approval.

💡 Engineering support: Free DFM within 48h — send your motor spec or drawing to linda_reenives@163.com.