SJ-2B4501TK (correct model, not “4501TK only variant”)

SJ-2B4501TK is a Mitsubishi Electric SJ-B series built-in AC spindle motor, used in medium-power CNC machining centers for general milling and turning applications.

It belongs to the SJ-2B450x family, which is one of the most commonly used “industrial built-in spindle motor” lines in older Mitsubishi CNC machines.

🔧 Verified specifications (official Mitsubishi data)

From Mitsubishi SJ-B series technical documentation:

Parameter	Value
Continuous rated output	7.5 kW
Short-time rated output	11 kW (30 min rating)
Acceleration/deceleration output	15 kW
Actual accel/decel output	18 kW
Base rotation speed	700 rpm (low-speed coil) / 1320 rpm (high-speed coil)
Maximum speed	10,000 rpm
Continuous torque	102 N·m / 54.3 N·m (coil dependent)
Short-time torque	150 N·m / 79.6 N·m
Rotor inertia	0.08 kg·m²
Mass	~47 kg (stator + rotor)
Cooling	Liquid/oil jacket cooling
Drive unit	MDS-D2-SP-200

🔧 Model code breakdown

Code part	Meaning
SJ	Mitsubishi spindle motor family
2B	SJ-B compact built-in spindle series
4501	7.5 kW class motor variant (standard configuration)
T	terminal / connector type

So:

SJ-2B4501TK = 7.5 kW built-in spindle motor for medium-duty CNC machining

⚙️ What makes SJ-2B4501TK important

This model is part of Mitsubishi’s workhorse spindle motor range, meaning it is designed for:

stable continuous cutting (not just peak speed)
good torque at low–mid RPM
reliable heavy-duty industrial use
compatibility with older Mitsubishi CNC systems

🏭 Typical applications

SJ-2B4501TK is used in:

vertical machining centers
general-purpose CNC milling machines
steel and cast iron cutting
boring and heavy drilling operations
industrial production lines

It is preferred when machines need:

⚖️ strong torque over ultra-high speed
🧱 rigid spindle performance
🎯 stable cutting under load
🔧 long-life industrial operation

⚖️ Position in Mitsubishi spindle lineup

Series	Role
SJ-2B	compact built-in spindles (low–mid power)
SJ-BG	modern high-speed built-in spindles
SJ-DG	high-torque cutting spindles
SJ-DL	external high-speed spindle motors

🧠 Simple explanation

SJ-2B4501TK is a 7.5 kW built-in CNC spindle motor designed for medium-duty machining, offering strong torque, reliable continuous cutting, and up to 10,000 rpm operation.

Mitsubishi M80 Built-IN Spindle Motor SJ-2B4501TK

Description