NEW Mitsubishi Servo Motor HC-SF81 HCSF81

HC-SF Series 850W High-Torque Low-Speed Motor designed for applications requiring substantial torque at moderate rotational speeds.

The Mitsubishi HC-SF81 servo motor is engineered specifically for high torque at low shaft speeds, making it ideal for CNC and automation applications where turning force is more critical than rotational velocity.

This 850W rated output motor delivers approximately 8.1 Nm of torque at 1,000 RPM—significantly higher than comparable motors running at 2,000 or 3,000 RPM. The output shaft features a smooth cylindrical design at φ24 mm with a 110 mm diameter flange, operating on three-phase AC 107V with 5.1 A rated current. This unventilated motor uses natural convection cooling and does not include an electromagnetic brake.

The HC-SF81's 1,000 RPM rated speed provides substantially more torque per watt than higher-speed equivalents, eliminating the need for reduction gearboxes in many applications. This direct coupling approach reduces backlash, improves dynamic response, and simplifies maintenance.

Ideal applications include:

The HC-SF81 uses an analog OBA encoder and is specifically designed for use with MR-J2 series servo amplifiers. This encoder architecture differs from digital serial encoders used in newer MR-J2S, MR-J3, and MR-J4 amplifiers, making direct substitution with newer motor variants impossible without changing the drive system.

For optimal thermal management, install on a 250 × 250 × 12 mm aluminum mounting plate or equivalent thermal mass. The smooth shaft design relies on coupling clamping force for torque transmission—consider keyed shaft variants for applications with frequent bidirectional torque reversals or axial loads.