One New Mitsubishi Servo Motor HC-SFS102B HCSFS102B HC-SFS102B New In Box Factory Sealed

Mitsubishi HC-SFS102B AC Servo Motor — 1 kW MELSERVO J2S with Electromagnetic Brake, New in Box

Precision motion control demands more than raw power — it requires a motor that holds position under load, responds instantly to commands, and keeps doing both day after day in a production environment. The Mitsubishi HC-SFS102B delivers all three, and this unit is offered factory sealed, new in original box, with the full specification intact.

The HC-SFS Series in Context

The HC-SFS102B belongs to Mitsubishi Electric's MELSERVO J2S series — the generation of AC brushless servo motors that became the workhorse of Japanese-controlled machine tools and automation equipment through the late 1990s and 2000s. Designed as a medium-inertia, medium-capacity motor, the HC-SFS family occupies the performance range where versatility matters most: enough torque and speed range to handle everything from precise contouring on a machining center to synchronized multi-axis motion on an automated assembly line.

The "B" suffix is the key distinction here. This motor includes a built-in electromagnetic brake — a holding brake that engages when power is removed, preventing the shaft from rotating under gravity or residual load. That's what separates it from the standard HC-SFS102 and makes it the correct choice for vertical axes, robotic joints, and any application where uncontrolled movement at power-off is a safety or precision concern.

Technical Specifications

The Electromagnetic Brake — Why It's There

On a horizontal axis, gravity isn't much of a factor. A motor shaft that loses power just stops, and the load stays where it is. Vertical axes are a completely different story.

When a servo drive loses power — whether from a programmed stop, an E-stop, or an unexpected power failure — a vertical axis without a holding brake will drop under gravity. At best, that means a positioning error on restart. At worst, it means a workpiece, fixture, or tool crashes into the machine table.

The HC-SFS102B's built-in electromagnetic brake engages the moment the motor is de-energized, holding the shaft against external torque. It's a spring-applied, electrically released design: spring force holds the brake closed, and applying voltage releases it. So even a total power loss defaults to the safe state — shaft locked, load held.

For robot joints, Z-axis spindle carriers, pallet lifters, and gantry systems, this makes the "B" variant the only appropriate choice.

17-Bit Absolute Encoder — 131,072 Positions per Revolution

The feedback system built into this motor is one of its most significant features. Mitsubishi's 17-bit absolute encoder provides 131,072 distinct position values per revolution — a resolution that gives the MELSERVO drive system the fine-grained data it needs for smooth velocity control and tight positioning accuracy.

More importantly, it's absolute: the encoder retains position information through power cycles using battery backup in the servo amplifier. When the machine restarts, the drive already knows exactly where each axis stands. No reference return required. No homing cycle delay. Just immediate readiness to run.

For production environments where restart time matters — multi-shift operations, cells that recover from emergency stops — the absolute encoder is a genuine operational advantage.

Compatible Drive Systems

The HC-SFS102B is designed for Mitsubishi's MELSERVO J2S series servo amplifiers, specifically the MR-J2S series. The motor and drive communicate via a dedicated encoder cable that carries the 17-bit absolute position data, with drive-side battery backup maintaining position through power-off. Compatible amplifier models for a 1 kW motor in this series include the MR-J2S-10A and MR-J2S-10B, depending on whether command input is analog or SSCNET (high-speed serial communication).

Always match the amplifier to the motor by both power class and interface type — the J2S system supports both analog speed/torque command and SSCNET digital position command, and the amplifier selection determines which CNC or motion controller the system can integrate with.

Where This Motor Is Used

The HC-SFS 1 kW range fills a practical slot in machine design: large enough for significant cutting and clamping forces, compact enough to fit in tight machine enclosures. With the added brake, the HC-SFS102B turns up in:

CNC Machining Centers — Z-axis spindle carrier drives where the brake prevents the head from dropping under gravity when the drive is de-energized

Multi-Axis Robots — joint drives on SCARA and articulated robots where holding torque between motions is essential for positional stability

Automated Assembly Equipment — press-fit and screwdriving axes where the motor must hold position at the end of a stroke without continued power to the drive

Injection Molding Machines — ejector and injection axis drives on electric injection molding equipment requiring precise position hold

Conveyor and Transfer Systems — indexing axes where gravity loading at rest justifies the brake version

New in Box — Factory Sealed

This unit is offered exactly as shipped from Mitsubishi Electric's factory — original packaging, factory seal intact, not installed, not powered, not repaired or refurbished. For a precision servo motor where bearing condition and encoder alignment are critical to long-term performance, buying new-in-box is the only way to be certain about the starting condition of the unit.

FAQ

Q1: What is the difference between the HC-SFS102 and the HC-SFS102B?

The only difference is the electromagnetic brake. The HC-SFS102 is the standard motor without a brake. The HC-SFS102B includes a built-in spring-applied electromagnetic brake that locks the shaft when power is removed. All other specifications — power, torque, encoder, speed, and physical dimensions — are identical. Choose the B variant for vertical axes, robot joints, or any load that must be held at rest without continuous power to the drive.

Q2: Which Mitsubishi servo amplifier is compatible with the HC-SFS102B?

The HC-SFS102B is designed for the Mitsubishi MELSERVO MR-J2S series amplifiers, specifically the MR-J2S-10A (analog command) or MR-J2S-10B (SSCNET digital command), which are rated for 1 kW motors in the 200 V class. Always confirm with the amplifier documentation that the encoder and brake interfaces match.

Q3: Does the electromagnetic brake require a separate power supply?

Yes. The brake in the HC-SFS102B is a spring-applied, electrically released type — it requires a DC voltage (typically 24 V DC) to release the brake and allow shaft rotation. The brake cable is separate from the motor power and encoder cables. The brake control is typically handled by the servo amplifier or a dedicated brake release relay in the control cabinet.

Q4: What does the 17-bit absolute encoder mean in practice?

It means the motor has 131,072 unique position values per revolution, and those positions are retained through power-off via battery backup in the servo amplifier. When the machine restarts, the drive already knows the axis position — no homing cycle is needed. This is the standard encoder for the J2S series and is a prerequisite for the absolute position retention function supported by MR-J2S amplifiers.

Q5: Is the HC-SFS102B still in production, or is it a discontinued model?

The HC-SFS series belongs to the MELSERVO J2S generation, which Mitsubishi has superseded with newer amplifier families (MR-J3, MR-J4, MR-J5). While newer motors offer improved performance, the J2S system remains in active service in a large installed base. New-in-box HC-SFS102B units are available through industrial automation parts channels. For long-term projects, verify amplifier availability alongside the motor.