Product Description:

The S31HMNA-RNNM-00 servo motor is manufactured by Pacific Scientific as part of the S Brushless Motors series. It is a 6-pole neodymium magnet brushless unit that supplies precise rotary motion for packaging stations, material-handling axes, and light machining fixtures. By using a size 21 frameless resolver for primary feedback inside a compact metric flange, the motor supports closed-loop control with modern drives while eliminating brush wear. This arrangement lets the drive monitor rotor position directly for stable speed and position control during repeated duty cycles.

At zero speed, the rotor can exert a continuous stall torque of 2.2 Nm without exceeding its thermal limit, and it can reach a peak value of 6.2 Nm during acceleration or short overloads. A torque constant of 0.7 Nm/ARMS links drive current to output torque and supports current-loop scaling. Electrical losses are governed by a line-to-line resistance of 4.1 ohms, and current rise time is shaped by the winding inductance of 10.3 mH; together these parameters influence heating and commutation behavior for the H-type stator windings. The motor is supplied without a holding brake, so external methods must secure vertical loads when power is removed, and the lack of a shaft seal limits use to clean, dry environments.

With a mass of 3.2 kg, the unit can be mounted on small frames while still providing the stiffness needed for dynamic moves. A rotor inertia of 0.18 ×10⁻³ kg·m² allows rapid speed changes with minimal controller effort, and the standardized NEMA 34 frame size aligns with readily available gearboxes and couplings. The voltage constant of 0.44 VRMS/rad/sec sets the back-EMF available for velocity loops used in speed estimation. Metric mounting holes, a single-stack lamination, and a motor-mounted MS connector simplify installation, while the lack of secondary feedback keeps wiring straightforward.