Rated Torque

The torque a motor can output continuously for a long time without overheating.

Rated torque is the torque a motor or joint module can output continuously under specified conditions (rated speed, ambient temperature, cooling method) without the windings exceeding their allowed temperature. It's fundamentally a thermal limit: more torque means more current and more heat, and the rated value is the point where heat generation and heat dissipation balance. It's listed alongside peak torque on spec sheets — peak is often several times the rated value, but can only be sustained briefly. When selecting a motor, engineers convert the torque profile over a full motion cycle into an equivalent value using root-mean-square (RMS), then compare that to rated torque: sustained loads, like an arm holding a payload for a long time or a humanoid standing for a long time, all need to fall within the rated range. Adding active cooling, such as liquid cooling, to a joint can raise the torque it can sustain.

ExampleAn arm holding a 1 kg object at 0.5 m from the shoulder generates about 4.9 N·m of gravitational torque at the shoulder from that alone; holding the pose for a long time requires the shoulder's rated torque to exceed the total gravitational torque, including the arm's own weight.

Also called

Continuous Torque

Related

Peak Torque · Torque-Speed Curve · Motor Thermal Derating / Overheat Protection · Liquid-Cooled Joint Actuators (Active Thermal Management) · Torque Constant (Kt) · Payload

Sources

What's Continuous Stall Torque vs Rated Torque vs Peak Torque? - Parker
maxon motor: Key information (datasheet explanations)