Product Description:

The S31HNNA-RNNL-00 is a 6-pole neodymium magnet brushless servo motor produced by Pacific Scientific for the S Brushless Motors series. As a compact actuator, it provides closed-loop motion when paired with a drive that interprets its size 21 frameless resolver feedback. Resolver feedback supplies rotor position data for electronic commutation and motion correction during operation. The motor fits directly into machines that follow the NEMA frame standard, allowing it to be used in indexing tables, feeders, or general-purpose positioning axes.

At stall, the rotor can hold 2.2 Nm continuously, while momentary accelerations reach 6.2 Nm. Each ampere of sinusoidal phase current produces about 0.7 Nm/ARMS, so current loop tuning can be scaled directly from commanded torque. The three-phase winding has 10.3 mH of line-to-line inductance, which affects the motor's electrical time constant and PWM carrier selection. Copper resistance is 4.1 ohms line-to-line, which affects I²R heating and the voltage required for rated current. Together with the 0.44 VRMS/rad/s voltage constant, these values help the controller predict back EMF and maintain velocity. This model uses the H winding option and is built in a single stack length.

The rotor inertia is 0.18 kg·m² × 10⁻³, which supports fast speed changes without excessive drive bandwidth. Total mass is 3.2 kg, which helps when the motor is mounted on moving assemblies. The housing follows the NEMA 34 frame footprint and taps, and power plus resolver conductors exit as 18-inch flying leads for flexible routing through cable tracks. This cable style also leaves more freedom when routing conductors through tight machine spaces. The motor ships without a holding brake, has no shaft seal, and carries no secondary feedback, so static holding and added sealing must be provided externally when needed. It is better suited to clean installations where the shaft area is not exposed to washdown or heavy contamination.