Description
SJ-DJ5.5/120-01 is a Mitsubishi Electric SJ-DJ series compact & lightweight CNC spindle motor designed for machining centers that require high spindle speed, lower inertia, and fast acceleration response.
The SJ-DJ family is Mitsubishi’s compact/lightweight spindle motor series, optimized for smaller and faster machine tool designs. (mitsubishielectric.com)
🔧 Key specifications (SJ-DJ5.5/120-01)
| Parameter | Value |
|---|---|
| Series | SJ-DJ |
| Type | Compact & lightweight AC spindle motor |
| Continuous rated output | 3.7 kW |
| Short-time rated output | 5.5 kW (25% ED) |
| Standard accel/decel output | 5.5 kW |
| Actual accel/decel output | 6.6 kW |
| Base speed | 1500 rpm |
| Maximum speed | 12,000 rpm |
| Continuous rated torque | 17.7 N·m |
| Frame number | B90 |
| Shaft diameter | Ø28 mm |
| Flange fitting diameter | Ø150 mm |
| Total length | 327 mm |
| Approx. mass | 26 kg |
| Protection class | IP54 (shaft excluded) |
| Compatible spindle drive | MDS-DJ-SP-100 / MDS-EJ-SP-100 |
These specifications are listed in Mitsubishi’s official MDS-DJ / MDS-EJ spindle system manuals. (mitsubishielectric-cnc.com)
⚙️ What makes “/120” different from “/100”
| Model | Max Speed | Main Character |
|---|---|---|
| SJ-DJ5.5/100-01 | 10,000 rpm | Higher torque focus |
| SJ-DJ5.5/120-01 | 12,000 rpm | Higher speed focus |
The /120 frame is optimized for:
- higher spindle speed
- fast acceleration/deceleration
- precision finishing operations
⚙️ What makes the SJ-DJ series different
Standard SJ-D
- Conventional spindle motor
- Heavier structure
- Higher rigidity for general machining
SJ-DJ
- Compact and lightweight
- Lower inertia rotor
- Faster spindle response
- Better suited for compact/high-speed machines
Mitsubishi officially classifies SJ-DJ as a “Compact & lightweight spindle motor” family. (mitsubishielectric.com)
🏭 Typical applications
Used in:
- compact machining centers
- high-speed vertical CNC mills
- drilling/tapping machines
- light-to-medium cutting applications
- production machines requiring quick spindle response
⚠️ Important notes
- Not a positioning servo motor
- Not a linear motor
- Requires Mitsubishi spindle drive electronics
- Cooling and bearing condition are important at 12,000 rpm
- Must use compatible Mitsubishi spindle amplifiers
🧠 Simple explanation
SJ-DJ5.5/120-01 is a compact, lightweight 5.5 kW-class CNC spindle motor optimized for high-speed machining up to 12,000 rpm with fast spindle acceleration.