Product Description:

The S31JMNA-RNNM-00 is a 6-pole neodymium-magnet brushless servo motor from Pacific Scientific’s S Brushless Motors series. Built as a direct-drive actuator, it supplies electronically commutated torque and speed for coordinated positioning tasks in automated machinery, material handling stations, and light-duty robotics. It is suited for closed-loop motion systems that require smooth response and accurate control without a separate transmission stage.

This model delivers a continuous stall torque of 2.2 Nm, giving the axis enough holding force to keep loads steady under rated current without motion. When short-duty bursts are required, the peak torque climbs to 6.2 Nm, providing almost three times the continuous capability for quick acceleration. Dynamic response is aided by the low rotor inertia of 0.18 × 10⁻³ kg·m², so speed can be reversed or stopped with minimal overshoot. Position feedback is obtained through a size 21 frameless resolver, allowing rotor angle to be read by the drive over a full 360° electrical cycle. The motor is supplied without a holding brake, so static load retention must be handled by the drive or an external clamp. There is no secondary feedback device, and the design omits a shaft seal, so installation in clean, dry areas is advised.

The unit weighs 3.2 kg, keeping moving mass low when mounted on linear stages. Its NEMA 34 frame conforms to industry face-mount dimensions, and the front flange follows metric mounting for compatibility with metric fasteners. Stator iron is built in a 1-stack length, the shortest option in the family, which reduces overall body depth while maintaining thermal margin. Power and feedback conductors terminate through a motor-mounted MS connector, so cable connections can be made without opening the housing. The short body depth helps the motor fit tighter machine layouts, and the connector arrangement supports access where cable space is limited.