SJ-2B4503TK (Mitsubishi Electric)

SJ-2B4503TK is a Mitsubishi Electric SJ-B series built-in AC spindle motor, used in medium-duty CNC machining centers. It belongs to the SJ-2B 4500-series spindle motors, which are designed for general-purpose machining with a balance of power, torque, and speed flexibility.

🔧 Verified specifications (official Mitsubishi data)

From Mitsubishi SJ-B series technical documentation:
(Mitsubishi Electric CNC Manual – SJ-B Series)

Parameter	Value
Continuous rated output	11 kW / 15 kW (coil dependent)
Short-time rated output	15 kW / 22 kW (30 min rating)
Acceleration/deceleration output	15 kW / 22 kW
Actual accel/decel output	18 kW / 26.4 kW
Base speed	475 rpm / 1250 rpm (coil dependent)
Maximum speed	2,000 rpm / 10,000 rpm
Continuous torque	221 N·m / 115 N·m
Short-time torque	302 N·m / 168 N·m
Rotor inertia	0.135 kg·m²
Frame size	160–295 mm class
Cooling	Liquid / oil jacket cooling

🔧 Model code breakdown

Code part	Meaning
SJ	Mitsubishi spindle motor family
2B	SJ-B built-in spindle series
4503	11–15 kW class winding / high-output configuration
TK	terminal / connector type

So:

SJ-2B4503TK = high-output 4500-series built-in spindle motor for medium CNC machining

⚙️ What makes SJ-2B4503TK important

Compared with other 4500-series motors:

Higher output class within the 4500 family
Stronger torque than 4501/4502 variants
Designed for heavier cutting loads while still maintaining 10,000 rpm capability

It is essentially a “heavy-duty balanced spindle” in the 2B lineup.

🏭 Typical applications

SJ-2B4503TK is used in:

vertical machining centers (VMCs)
general-purpose CNC milling machines
steel and cast iron cutting
boring and drilling operations
industrial production machining systems

It is selected when machines require:

⚖️ strong balance of speed and torque
🧱 stable cutting under load
🎯 reliable continuous machining performance
🔧 compatibility with Mitsubishi MDS-D2 spindle drives

⚖️ Position in Mitsubishi spindle lineup

Series	Role
SJ-2B	compact built-in spindle motors (older generation)
SJ-BG	modern high-speed integrated spindles
SJ-DG	high-torque cutting spindles
SJ-DL	external high-speed spindle motors

🧠 Simple explanation

SJ-2B4503TK is a high-output 11–15 kW built-in CNC spindle motor designed for medium-to-heavy machining, offering strong torque, stable cutting, and full industrial duty performance up to 10,000 rpm.

Mitsubishi M80 Built-IN Spindle Motor SJ-2B4503TK

Description