Mitsubishi HC-SFS103K AC Servo Motor — 1.0 kW, 3,000 rpm, Keyed Shaft

Condition: Brand New · Original Packaging · Factory Sealed

Part Number: HC-SFS103K

Series: HC-SFS | Compatible Amplifiers: MR-J2S / MR-J3 / MR-J4

Overview

One kilowatt. Three thousand rpm. Keyed shaft — because friction alone isn't always enough.

The Mitsubishi HC-SFS103K is a 1.0 kW AC servo motor running at a rated speed of 3,000 rpm, producing 3.18 N·m of continuous torque with a peak of 9.55 N·m. It's the higher-speed variant in the HC-SFS 1.0 kW range — chosen when the application demands fast axis response and short cycle times rather than maximum torque at low speed.

The keyed shaft is the defining feature of this variant. Where the standard HC-SFS103 relies on a friction-fit coupling, the K version adds a machined keyway — a positive mechanical lock that keeps the driven component fixed to the shaft under load reversals, sustained torque, and the kind of shock loading that gradually works a plain-bore coupling loose over time.

Every unit ships brand new, sealed in its original Mitsubishi factory carton. Uninstalled. Unpowered. No rework, no prior field use, no exceptions.

Key Specifications

Why the Keyed Shaft Changes the Specification

It's a small detail with meaningful consequences at the machine level.

A straight-shaft servo motor transmits torque through the clamping force of the coupling alone. That works reliably in many applications — particularly those using precision servo couplings with consistent, predictable loads. But certain conditions put progressive stress on friction-fit connections: repeated load reversals that rock the coupling back and forth, sustained high torque near the rated continuous value, shock loads from indexing mechanisms or presses, and belt or chain drives where radial tension adds a secondary load to the shaft interface.

In any of these environments, the keyed shaft is the more durable solution. The keyway engages the coupling, pulley, or gear hub mechanically — torque is transmitted through the key itself, not through clamping friction. There's no slip, no gradual fretting, no need to periodically check and re-torque the coupling after run-in.

At 1.0 kW with a peak torque of 9.55 N·m, the HC-SFS103K sits in a range where the choice between shaft variants is a real engineering decision, not an afterthought. If the driven component needs a keyed bore — or if the application history includes coupling slip with straight-shaft motors — the 103K is the correct specification.

Performance Built for High-Cycle Environments

Speed that shortens cycle time. At 3,000 rpm, the HC-SFS103K traverses faster than the 1,000 rpm or 2,000 rpm variants in the same power class. In pick-and-place systems, transfer equipment, and multi-axis machining cells, faster axis traverse directly reduces non-productive time between operations.

Absolute position, no homing routine. The 17-bit encoder retains shaft position across power cycles. After a restart, an e-stop, or an unplanned outage, the controller has accurate position data immediately — no slow homing sequence, no lost index count, no manual recovery procedure. In multi-shift production environments, that translates directly to faster restarts and fewer operator interventions.

IP65 shaft sealing. Rated to resist pressurized water and fine dust at the shaft entry point. Relevant in machining cells where coolant mist is a constant, in press rooms with airborne metal particulate, and in food or pharmaceutical-adjacent equipment where periodic washdown is standard practice.

Class F insulation. Handles higher sustained winding temperatures than Class B motors — important in applications running long duty cycles in warm machine enclosures where motor cooling is limited to natural convection.

Amplifier compatibility across three generations. Works with MR-J2S, MR-J3, and MR-J4 series amplifiers. Maintenance teams managing equipment installed at different points in time can stock a single motor variant that fits multiple drive generations without managing separate part numbers.

Typical Applications

Small CNC Machining Centers & Lathes — Feed axes and auxiliary drives on compact machine tools where 1.0 kW at 3,000 rpm provides the right speed-torque profile for light to medium cutting loads and fast rapid traverse.

Pick-and-Place & Handling Equipment — High-speed positioning axes in assembly and transfer systems where cycle time is the primary performance metric and shaft integrity under rapid direction changes matters.

Laser Cutting & Marking Systems — Positioning axes where encoder precision and fast response directly affect cut accuracy, mark registration, and throughput.

Indexing Tables & Rotary Positioners — Driven through reducers with keyed shaft connections, where the motor must accelerate and decelerate a rotary load accurately and repeatedly across long production runs.

Packaging Machinery — Axis drives in form-fill-seal, cartoning, and labeling equipment where consistent velocity control and reliable positioning affect product quality and line efficiency.

Textile & Winding Equipment — Feed and traverse axes where the motor connects to a driven roller or winding element through a keyed coupling, and where shaft slip would directly affect material tension control.

A Note on Availability for the K Variant

Keyed shaft variants consistently represent a smaller share of distribution inventory than their straight-shaft counterparts — they serve a narrower segment of applications, so fewer units get stocked at each level of the supply chain. When an HC-SFS103K fails unexpectedly, sourcing a verified-new replacement quickly is rarely straightforward. Production facilities with active installations and system integrators building to customer schedules both benefit from having a sealed spare on hand before the need arises.

Frequently Asked Questions

Q1: What is the difference between the HC-SFS103 and the HC-SFS103K?

A: The HC-SFS103 has a standard straight shaft; torque is transmitted through the clamping force of the coupling. The HC-SFS103K adds a machined keyway, providing a positive mechanical connection between the shaft and the driven component. Specify the K variant when the application uses keyed couplings, pulleys, or gears, or when operating conditions — load reversals, shock loads, or sustained high torque — make a friction-only connection unreliable over time.

Q2: Which servo amplifiers are compatible with the HC-SFS103K?

A: The HC-SFS103K is compatible with Mitsubishi MR-J2S, MR-J3, and MR-J4 series servo amplifiers. Confirm the amplifier's rated output matches the motor's 1.0 kW / 200V specification and that the encoder cable and power connector types are correct for the amplifier generation being used.

Q3: Does the HC-SFS103K include a built-in electromagnetic brake?

A: No. The HC-SFS103K is the standard non-brake variant. For vertical axis applications or any setup where the load must be held mechanically on power loss, the HC-SFS103BK — which combines the keyed shaft with an integrated electromagnetic brake — is the correct specification.

Q4: What are the exact keyway dimensions for the HC-SFS103K shaft?

A: Keyway dimensions follow JIS B 1301 standards as defined in Mitsubishi Electric's official HC-SFS series mechanical specification drawings. Refer to the current Mitsubishi servo motor catalog or specification sheet for the precise key width, height, depth, and shaft diameter before machining any mating coupling or hub bore.

Q5: Does the 17-bit absolute encoder need a battery to retain position after power loss?

A: Single-turn absolute position is retained without a battery. For multi-turn absolute operation — where the system needs to track position across multiple full shaft revolutions through a power cycle — a battery backup is required on the amplifier side. This is an amplifier-level requirement and is consistent across all HC-SFS motor variants, not specific to the HC-SFS103K.