Mitsubishi Servo Motor HC-SFS502K HCSFS502K HC-SFS5O2K

Mitsubishi HC-SFS502K | MELSERVO J2-Super 5 kW Servo Motor — Keyed Shaft / 23.9 Nm / 17-Bit Absolute

Part Number: HC-SFS502K

Manufacturer: Mitsubishi Electric (Japan)

Series: MELSERVO J2-Super — HC-SFS

Rated Output: 5 kW

Rated Speed: 2,000 rpm (max 3,000 rpm)

About This Motor

The HC-SFS502K is the 5 kW member of Mitsubishi's HC-SFS medium-inertia 2000 rpm servo motor family, matched to the MR-J2S-500 amplifier. It handles the heavier end of industrial servo applications: ball-screw feed drives on machining centres, winding tension drives, press and stamping feed axes, and rotary indexing tables where 23.9 Nm continuous torque and 71.6 Nm peak are needed.

The 17-bit absolute encoder (131,072 ppr) reports multi-turn position on power-up without homing. The backup battery for the multi-turn counter is in the MR-J2S-500 amplifier — not in the motor — and is replaceable without disturbing the motor or coupling.

Keyed shaft: Torque transmits through the key, not through friction clamp force. This matters at 71.6 Nm peak — friction couplings can develop intermittent slip over service years, producing subtle position repeatability loss that is hard to diagnose. A positive keyway drive does not degrade with service hours. Hub installation: always use a drawbolt at the shaft-end thread to pull the hub axially into position. Never press or hammer — impact loading at the 176 mm frame travels directly to the encoder disc.

No brake: Position is held at servo-on by the amplifier's closed position loop. Correct for horizontal and balanced axes. Vertical or gravity-loaded axes require the HC-SFS502BK (spring-applied brake, engages on power loss).

Key Specifications

Compatible Amplifiers

• MR-J2S-500A — pulse / analog command, general-purpose positioning
• MR-J2S-500B — SSCNET fiber bus, Mitsubishi A/Q motion controllers
• MR-J2S-500CP — built-in 31-point positioning table, no external controller needed

The HC-SFS502K requires MR-J2S (J2-Super). Original MR-J2-500 amplifiers cannot read the 17-bit encoder. MR-J3 and MR-J4 require a renewal adapter kit.

FAQ

Q1: What amplifiers are compatible?

MR-J2S-500A, -500B, or -500CP. Not compatible with original MR-J2-500 (14-bit encoder protocol only), MR-J3, or MR-J4 without a renewal adapter.

Q2: HC-SFS502K vs HC-SFS502BK — what's the difference?

Identical electrically. The BK adds a spring-applied brake (locks on power loss). Use the BK on vertical axes and gravity-loaded mechanisms. The 502K is correct for horizontal axes where servo lock holds position.

Q3: Can HC-SFS502K replace an HC-SF502K?

Same mechanical fit — flange, shaft, keyway. Different encoder: HC-SF502K is 14-bit (MR-J2 and MR-J2S compatible); HC-SFS502K is 17-bit (MR-J2S only). If the machine runs original MR-J2-500, use HC-SF502K. If on MR-J2S-500, HC-SFS502K is correct — verify electronic gear ratio settings.

Q4: Where is the encoder backup battery?

Inside the MR-J2S-500 amplifier (Mitsubishi A6BAT lithium). Replace at battery-low alarm. Full discharge resets the multi-turn counter and requires a reference-return cycle before production.

Q5: Discontinued — what are the options?

Surplus and refurbished stock is widely available for machines staying on J2-Super. Long-term new-design replacement: HG-SR502K (MR-J4 series, 5 kW, 2000 rpm, keyed shaft, 22-bit, IP67, requires MR-J4-500A).