The HG-SR301J is a Mitsubishi servo motor from the HG-SR series, rated for 3.0 kW output at 1000 r/min. The 'J' suffix indicates an integrated oil seal, which protects the motor bearing from lubricant ingress in geared or direct-drive applications where the motor shaft interfaces with a gearbox or coupling that contains oil.
What the ratings mean for fit
The 3.0 kW rating at 1000 r/min defines the continuous mechanical output at the shaft. This is a low-speed, high-torque profile compared to a 2000 or 3000 r/min motor of similar power — expect roughly 28.6 N·m rated torque. That torque density suits direct-drive or low-ratio applications like indexing tables, rotary axes, or conveyor drums where the motor runs near the load speed without a gearbox. The oil seal (J variant) is a material difference from the standard HG-SR motor. If your application has a gearbox splash-lubricated at the shaft pass-through, this seal prevents oil migration into the motor winding. No oil seal means eventual seal failure and motor replacement in those environments.
Where it is used
Servo motors of this class power precise motion axes in machine tools, packaging lines, robotic cells, and material handling equipment. The HG-SR series is Mitsubishi's standard servo line for MELSERVO-J4 drives. The indoor-only ambience spec (no direct sunlight, free from corrosive gas, oil mist, dust) means it belongs in a protected cabinet or machine enclosure — not in a washdown or outdoor location.