SJ-BG150D/150-01☐ (Mitsubishi Electric)

SJ-BG150D/150-01☐ is a Mitsubishi Electric SJ-BG series built-in AC spindle motor, designed for high-precision CNC machining centers requiring:

integrated spindle motor construction
high rigidity
stable thermal performance
medium/high-speed heavy cutting capability

It belongs to Mitsubishi’s built-in spindle motor family (SJ-BG), where the motor is directly integrated into the spindle housing instead of using a belt or external spindle motor.

🔧 Model code breakdown

Code section	Meaning
SJ	Mitsubishi spindle motor family
BG	Built-in spindle motor series
150D	150 mm frame, D-type high-rigidity structure
150	15,000 rpm class
01	design/winding version
☐	OEM/custom specification option

So:

SJ-BG150D/150-01☐ = 150 mm built-in spindle motor designed for ~15,000 rpm precision machining with high rigidity and integrated spindle construction

🔧 Verified specifications

From Mitsubishi’s official SJ-BG spindle motor specification manual:

Parameter	Value
Series	SJ-BG
Motor type	Built-in AC spindle motor
Continuous rated output	3.7 kW
Short-time rated output	5.5 kW (40% ED)
Standard accel/decel output	5.5 kW
Actual accel/decel output	6.6 kW
Continuous base speed	2500 rpm
Short-time base speed	2500 rpm
Maximum speed	15,000 rpm
Frame/core size	90-100 class
Continuous torque	14.1 N·m
Cooling	Liquid/oil jacket cooling
Compatible drive	MDS-E-SP-80 / MDS-E-SP2-16080(M)

⚙️ What makes the “150D” variant special

Within the SJ-BG family:

Variant	Positioning
090A/B/D	Compact ultra-high-speed spindles
110F	Higher rigidity compact spindle
120C	Stronger 20k rpm spindle
150D	Larger high-rigidity 15k rpm spindle for heavier cutting

The D-type generally indicates:

improved rigidity
stronger thermal stability
better continuous cutting performance
suitability for heavier machining loads

Compared with smaller BG motors, the 150D version is optimized more for:

stable cutting force
spindle stiffness
sustained machining accuracy

rather than only maximum RPM.

⚙️ What “☐” means

The square placeholder:

☐ = optional OEM/machine-builder configuration code

This may define:

encoder specification
bearing preload
cooling configuration
connector orientation
balancing grade
machine-specific customization

🏭 Typical applications

SJ-BG150D/150-01☐ is commonly used in:

high-speed machining centers
mold & die machining
precision milling
aerospace finishing
compact integrated spindle units
continuous precision production machining

It is selected when machines need:

⚡ integrated high-speed spindle construction
🎯 high contour accuracy
🧱 strong spindle rigidity
📉 low vibration and thermal growth

⚖️ Position in Mitsubishi spindle lineup

Series	Role
SJ-V	General machining spindle motors
SJ-VL	Low-inertia tapping/drilling
SJ-DG	High-torque cutting spindle
SJ-DL	Ultra high-speed external spindle
SJ-BG	Built-in integrated spindle motors

Official Mitsubishi spindle documentation identifies SJ-BG as the built-in spindle series.

🧠 Simple explanation

SJ-BG150D/150-01☐ is a built-in CNC spindle motor designed for precision machining up to about 15,000 rpm, combining integrated spindle construction with higher rigidity and stable continuous cutting performance.

Mitsubishi M80 Built-IN Spindle Motor SJ-BG150D/150-01☐

Description