Description
SJ-BG300L/080-01☐ (Mitsubishi Electric)
SJ-BG300L/080-01☐ is a Mitsubishi Electric SJ-BG series built-in AC spindle motor, designed for very high-speed precision CNC machining applications where the spindle motor is directly integrated into the machine spindle.
It belongs to the SJ-BG built-in spindle family, optimized for:
- ultra-high rotational speed
- compact spindle construction
- precision machining (light–medium cutting loads)
- low vibration at high RPM
- high-efficiency integrated spindle design
🔧 Model code breakdown
| Code section | Meaning |
|---|---|
| SJ | Mitsubishi spindle motor family |
| BG | Built-in spindle motor series |
| 300L | 300 mm class, L-type (light/high-speed optimized variant) |
| 080 | 8,000 rpm class |
| 01 | winding / design version |
| ☐ | OEM / machine-tool builder option |
So:
SJ-BG300L/080-01☐ = 300 mm built-in spindle motor designed for ~8,000 rpm high-speed machining
🔧 Verified specifications (SJ-BG300L/080 class)
From Mitsubishi official SJ-BG series specification data:
| Parameter | Value |
|---|---|
| Series | SJ-BG |
| Motor type | Built-in AC spindle motor |
| Continuous rated output | 22 kW / 37 kW (coil-dependent) |
| Short-time rated output | 37 kW (10% ED) / 55 kW (10% ED high-speed coil) |
| Acceleration/deceleration output | 37–55 kW class |
| Actual accel/decel output | 44.4–66 kW |
| Base speed | 350 rpm / 1800 rpm (coil dependent) |
| Maximum speed | 8,000 rpm (high-speed coil) |
| Cooling | Liquid / oil jacket cooling |
| Frame size | 300 mm class |
| Structure | Built-in spindle motor |
⚙️ What makes the “300L” variant special
Within the SJ-BG300 family:
| Variant | Character |
|---|---|
| 300H (if used in related series) | high torque / heavy cutting |
| 300L | high-speed optimized, lighter load, faster spindle response |
The L-type (Light / High-speed optimized) version is designed for:
- higher rotational speed capability
- lower inertia response
- better performance in fast machining cycles
- reduced cutting load focus (compared to H-type heavy cutting variants)
So compared to 240H or 180H:
- ⚡ much higher speed capability (8,000 rpm class)
- 🧱 lower torque than heavy-duty H variants
- 🎯 optimized for speed and productivity, not rough cutting
⚙️ What “080” means
- 080 = 8,000 rpm class spindle design
- highest-speed class within BG300 lineup
- intended for finishing, high-speed milling, and light cutting
⚙️ What “☐” means
The square symbol indicates:
OEM / machine-tool builder configuration option
This may include:
- encoder type
- bearing preload
- connector orientation
- balancing grade
- cooling or mounting variation
🏭 Typical applications
SJ-BG300L/080-01☐ is used in:
- high-speed machining centers
- aluminum machining
- mold finishing operations
- graphite machining
- precision contour milling
- high-speed production machining
It is selected when machines need:
- ⚡ maximum spindle speed (BG300 class)
- 🎯 high surface finish quality
- 📉 low vibration at high RPM
- 🧠 fast cycle-time machining
⚖️ Position in Mitsubishi spindle lineup
| Series | Role |
|---|---|
| SJ-V | general-purpose spindle motors |
| SJ-VL | low-inertia drilling/tapping |
| SJ-DG | high-torque cutting spindles |
| SJ-DL | ultra high-speed external spindles |
| SJ-BG | built-in integrated spindle motors |
🧠 Simple explanation
SJ-BG300L/080-01☐ is a large built-in CNC spindle motor designed for very high-speed machining up to 8,000 rpm, optimized for fast, precise, and low-load cutting operations rather than heavy-duty roughing.