Product Description:

Pacific Scientific offers the S Brushless Motors series for compact motion tasks, and the S21GNNA-RNNL-00 sits in the middle of that range. This 6-pole neodymium magnet brushless servo motor is intended for light-duty axes that need accurate speed or position control in automated machinery. Because the frame follows the NEMA 23 outline, it can bolt directly to standardized gearheads, linear stages, or small conveyor drives without custom brackets.

The motor delivers a continuous stall capability of 0.5 Nm, giving holding power for static loads while staying within its thermal limits. When short bursts of acceleration are required, the available peak reaches 1.36 Nm. Electrical performance is tied to a line-to-line resistance of 12.0 Ohms and an inductance of 14.4 mH, which influence current rise time and help with amplifier sizing. Mechanical integration is simplified by the NEMA 23 mounting face, and electrical hookup is through 18-inch flying leads, so no separate connector kit is needed. A size 21 frameless resolver supplies primary feedback, and the motor uses winding code G with a single lamination stack. The unit is supplied without a holding brake or a shaft seal, which keeps inertia low and suits clean, dry environments.

Dynamic characteristics are shaped by a torque constant of 0.3 Nm/ARMS, allowing the controller to predict output torque from commanded current. The rotor inertia is only 0.042 kg·m²×10⁻³, so speed changes can occur rapidly with minimal overshoot. Overall motor weight is 1.4 kg, easing carriage loads on linear slides and reducing support structure size. A voltage constant of 0.19 VRMS/rad/sec indicates the back EMF developed per unit speed and helps with regenerative voltage calculations. No secondary feedback device is present, so primary position information comes from the resolver alone.