Product Description:

The S31GNNA-RNUM-00 servo motor is built by Pacific Scientific and belongs to the S Brushless Motors series. As a 6-pole neodymium magnet brushless servo motor, it converts electrical energy into controlled rotational motion for positioning, indexing, and velocity control tasks in automated machinery. The model is supplied without a holding brake, so external means must secure loads during power loss. A NEMA frame mounting interface lets it fit standard motor plates used in packaging, material-handling, and electronics assembly lines.

The motor produces a continuous stall torque of 2.2 Nm, which is the maximum steady torque it can deliver at zero speed without overheating. For transient demands such as acceleration, the peak torque rises to 6.2 Nm. Electrically, the three-phase stator winding shows an inductance of 41.2 mH, which shapes current rise time and influences drive tuning, while its line-to-line resistance measures 16.4 ohms and affects copper losses at rated current. The housing follows the NEMA 34 frame envelope, so shafts, flanges, and bolt patterns match common stepper and servo footprints. A size 21 frameless resolver supplies primary feedback, and winding code G is paired with a single-stack lamination.

The rotor plus housing weighs 3.2 kg, providing moderate mass for quick installation without special lifting gear. During speed reversals, control algorithms must account for a rotor inertia of 0.18 × 10⁻³ kg·m², a low value that supports rapid position changes with limited drive power. The motor has a torque constant of 1.3 Nm/ARMS, meaning each ampere of sinusoidal phase current yields that amount of torque, and its back-EMF voltage constant is 0.82 VRMS/rad/sec, which the drive uses for commutation and speed estimation. A motor-mounted MS connector terminates power and resolver leads, and no secondary feedback device is included.