Mitsubishi M80 Built-IN Spindle Motor SJ-2B6914TK

🔧 Mitsubishi SJ-2B6914TK – Description (SJ-B Series Built-in Spindle Motor)

The SJ-2B6914TK is a high-capacity Mitsubishi Electric SJ-B series built-in spindle motor used in CNC machine tools that require very high torque at low speed and stable heavy cutting performance. It is designed for direct spindle integration, giving high rigidity and excellent cutting stability for large machining centers.

⚙️ Key Description

• Series: SJ-B Built-in Spindle Motor
• Type: Dual-coil spindle motor (low-speed / high-speed winding)
• Application: Heavy-duty CNC machining centers, large VMCs, high-load milling machines
• Drive compatibility: MDS-D2-SP-640 spindle drive unit

⚡ Functional Characteristics

• Uses coil changeover system:
  • Low-speed coil → extremely high torque for rough machining
  • High-speed coil → finishing / higher spindle speed operation
• Designed for:
  • Maximum cutting stability under heavy load
  • Large tool / large workpiece machining
  • Continuous industrial duty operation

📊 Key Performance Overview

• Power output:
  • Continuous: 25 kW (low-speed & high-speed coil)
  • Short-time (30 min): 30 kW
• Acceleration / deceleration output:
  • Standard: 30 kW
  • Actual peak: 36 kW
• Torque:
  • Continuous: 995 N·m (low-speed coil) / 508 N·m (high-speed coil)
  • Short-time: 1194 N·m / 610 N·m
• Speed range:
  • Low-speed coil: ~240 r/min base
  • High-speed coil: ~470 r/min base
  • Maximum speed: 1000 / 3300 r/min

🧩 Mechanical & Construction Details

• Rotor inertia: ~1.105 kg·m²
• Motor mass: ~143 kg (stator), ~91 kg (rotor)
• Stator diameter: ~Ø369.5 mm
• Rotor inner diameter: ~Ø165 mm
• Motor length: ~520 mm
• Cooling: Liquid/oil cooling required (~9.48 kW heat dissipation)

🏭 Typical Applications

The SJ-2B6914TK is used in:

• Large CNC vertical machining centers (heavy-duty VMCs)
• High-load roughing and deep-cut machining
• Industrial production machines with large diameter tools
• Applications requiring maximum spindle torque and rigidity

⚠️ Summary

The SJ-2B6914TK is one of the highest-torque models in the SJ-B 6900 series, characterized by:

• Very high torque (~1200 N·m short-time)
• Strong inertia for vibration stability
• Lower spindle speed compared to smaller SJ-B models
• Optimized for heavy rough machining rather than high-speed finishing