Mitsubishi HC-SFS353 AC Servo Motor — 3.5 kW MELSERVO J2S Series, New in Box Factory Sealed

When an application demands serious power — sustained high torque, rapid response, and 3,000 rpm operating speed — the component list gets shorter. At 3.5 kW, the Mitsubishi HC-SFS353 sits at the upper end of the HC-SFS medium-capacity lineup, and its combination of 11.1 Nm rated torque, 3,000 rpm rated speed, and 17-bit absolute position feedback puts it in a tier that handles the most demanding CNC and industrial automation axes. This listing is for a brand-new, factory-sealed unit in original Mitsubishi Electric packaging — never installed, never powered on.

Where the HC-SFS353 Fits

The HC-SFS series covers Mitsubishi's medium-inertia, medium-capacity segment within the MELSERVO J2S platform. The 353 sits at 3.5 kW within the 3,000 rpm sub-family, making it the natural choice for primary motion axes on large machining centers, heavy rotary tables, and high-load industrial robot joints where both speed and torque margin are non-negotiable.

The step up to the 176 × 176 mm flange — larger than the 130 mm frame used by the 1–2 kW HC-SFS models — reflects the physical reality of moving 11.1 Nm continuously. The motor body is proportionally larger, and the mechanical interface is designed for the heavier machine structures typical of this power class.

Technical Specifications

Running at 3,000 rpm — What That Means for the Machine

The HC-SFS353 belongs to the 3,000 rpm sub-series of the HC-SFS family, which prioritizes a wider usable speed band compared to the 2,000 rpm variants at equivalent power. At 11.1 Nm rated torque and 3,000 rpm rated speed, the motor delivers its full continuous output capability at a speed that accommodates both the working feed rate of a production cut and the rapid traverse of an empty tool return — without stepping into a derated operating zone.

The 3,000 rpm rated speed also means faster cycle times in applications where motion profiles are constrained by the motor's continuous operating ceiling. On a CNC turning center or machining center's primary feed axis, the difference between a 2,000 rpm and 3,000 rpm rated speed motor can translate directly into reduced cycle time per part.

Absolute Encoder — 131,072 ppr, No Homing Required

Every HC-SFS353 ships with a built-in 17-bit absolute optical encoder — 131,072 discrete positions per shaft revolution — transmitting position via Mitsubishi's high-speed serial link directly to the servo amplifier.

The practical consequence of an absolute encoder is immediate position awareness from cold start. With the battery installed in the servo amplifier, multi-turn position data is preserved through power-off states. When the machine powers on, the axis is already referenced — no homing routine, no reference return sequence, no delay before the machine is ready for work.

For production environments running multiple shifts with regular power cycling, this is a meaningful operational advantage. Every hour over a machine's service life adds up when multiplied across every startup it performs.

Oil Seal and IP65 — Protection Where the Work Gets Dirty

The shaft bore of the HC-SFS353 is sealed with a dedicated oil seal at the drive-end face. On machine tools, the shaft penetration is the most vulnerable point — the one location where cutting fluid, coolant mist, and fine metallic swarf have the shortest path to the bearing cavity and encoder.

The oil seal closes that path. Combined with the IP65-rated housing, which provides full protection against dust and directed water jets, the motor is built to survive the environment of an active machine tool or industrial manufacturing cell without secondary enclosure provisions.

Compatible Servo Amplifiers

The HC-SFS353 is designed to operate with the Mitsubishi MR-J2S-350A (analog command / pulse-train interface) or MR-J2S-350B (SSCNET digital network interface) servo amplifiers, both rated at 3.5 kW.

Interface selection depends on the control architecture. The MR-J2S-350A suits systems where the upstream controller — a PLC, CNC, or standalone motion controller — issues commands via pulse train or analog voltage reference. The MR-J2S-350B is used in multi-axis SSCNET systems controlled by Mitsubishi's A-series or Q-series motion controllers, where all axes are synchronized over a high-speed fiber-optic network.

Typical Application Areas

Large-format CNC machining centers — X, Y, and Z feed axes on horizontal and vertical machining centers where large ballscrew assemblies and heavy table masses demand both 3.5 kW output and high torque at speed

CNC turning centers and lathes — Z and X-axis servo drives on heavy-duty turning centers performing aggressive material removal cycles

4th and 5th axis rotary tables — Direct or geared drive of heavy rotary and tilting table mechanisms where 11.1 Nm continuous torque provides the holding and positioning authority the application requires

Industrial robots — Shoulder and waist joints on medium-to-large-payload articulated robot arms, where the load inertia at extended reach places the highest demands on the drive motor

Automated welding and cutting systems — Gantry and portal motion axes on large-format cutting tables and robotic welding cells where consistent speed under variable load is critical to weld or cut quality

Material handling and conveyor systems — High-load indexing drives, pallet handling systems, and automated warehouse retrieval mechanisms where 3.5 kW provides the torque margin to move heavy loads reliably on every cycle

Suffix Variants

The HC-SFS353 base motor is available in several configurations:

• HC-SFS353 — straight shaft, no brake (this listing)
• HC-SFS353B — with built-in electromagnetic brake
• HC-SFS353K — keyed shaft
• HC-SFS353BK — electromagnetic brake and keyed shaft

All variants share the same 3.5 kW output, 17-bit absolute encoder, IP65 protection, and 176 × 176 mm flange. The base straight-shaft model is the correct selection when the coupling is keyless (clamp-type) and no shaft-locking brake is required.

FAQ

Q1: Which servo amplifier is compatible with the HC-SFS353?

The HC-SFS353 pairs with the MR-J2S-350A for analog/pulse-train command systems or the MR-J2S-350B for SSCNET-networked multi-axis motion systems. Both amplifiers are rated at 3.5 kW and are the correct match for this motor within the MELSERVO J2S platform.

Q2: What is the difference between the HC-SFS352 and HC-SFS353?

Both motors are 3.5 kW medium-inertia AC servo motors from the HC-SFS series, but they belong to different speed sub-families. The HC-SFS352 has a rated speed of 2,000 rpm (higher torque at lower speed); the HC-SFS353 is rated at 3,000 rpm, offering a wider usable speed range and faster axis traverse. Motor selection depends on the application's torque-speed curve.

Q3: Does the HC-SFS353 support absolute position retention through a power-off cycle?

Yes. With a battery (Mitsubishi A6BAT) installed in the servo amplifier, the 17-bit absolute encoder retains multi-turn position data when mains power is removed. On the next power-up, the axis position is immediately available — no homing or reference return cycle is required.

Q4: Is the HC-SFS353 still in production?

The HC-SFS series is part of the MELSERVO J2S generation, which has been superseded by Mitsubishi's J4 and J5 series. New-in-box HC-SFS353 units remain in circulation for machine maintenance, spare parts holding, and retrofit projects. The current-generation equivalent in Mitsubishi's catalog is the HG-SR series (MELSERVO-J4).

Q5: Can the HC-SFS353 be used in vertical axis applications?

The base HC-SFS353 (no brake) is suitable for horizontal and lightly loaded vertical axes. For vertical axes where the load must be held securely when servo power is removed, use the HC-SFS353B variant, which includes a spring-applied electromagnetic brake that locks the shaft in the de-energized state. Mitsubishi's general guidance is that vertical load unbalance torque should remain within 70% of rated torque for reliable operation.