Product Description:

The S21HSNA-RNNM-04 belongs to the S Brushless Motors series engineered by Pacific Scientific. It is a 6-pole Neodymium magnet brushless servo motor intended to deliver precise position and velocity control on compact industrial axes such as small gantries, metering pumps, or labeling heads. Integration is straightforward because the motor is supplied with a motor-mounted MS connector for power and feedback, and its resolver supplies absolute rotor angle information directly to the drive.

The continuous stall torque of 0.5 Nm is the steady load the shaft can support without movement, while the peak rating of 1.36 Nm covers short acceleration bursts during indexing moves. A torque constant of 0.2 Nm/ARMS ties output torque to phase current, allowing the drive to predict load response accurately. Copper loss is governed by the phase-to-phase resistance of 3.0 ohms, and current rise time is shaped by the phase inductance of 3.7 mH; together, these electrical values influence thermal performance and current loop bandwidth. One H-type winding and a single-stack lamination ensure that the magnetic circuit matches the stated torque figures. The unit is built without a holding brake or a shaft seal, so external measures must handle static load retention and contaminant ingress. A size 21 frameless resolver supplies the primary feedback signal, and no secondary transducer is fitted. Stack length is limited to one section, which keeps the overall length short and rotor inertia low.

A frame size of NEMA 23 lets the motor bolt directly onto standardized 57 mm mounting patterns common in light-duty machinery. The back-EMF constant of 0.13 VRMS/rad/sec aligns with servo drives that operate on moderate DC bus voltages, simplifying component selection. Total mass is only 1.4 kg, so the load on linear slides and belt stages remains minimal. Rotor inertia is just 0.042 kgm^2 × 10⁻³, providing rapid speed reversals without excessive servo gain.