Product Description:

The S21GNNA-RNNC-00 is a brushless servo motor produced by Pacific Scientific within the S Brushless Motors series. As a 6-pole neodymium magnet unit, it delivers closed-loop rotary motion for compact actuators, pick-and-place heads, and other precision axes in automated equipment. The motor follows the NEMA frame mounting standard, allowing straightforward interchange with existing mounting hardware, and the size 21 frameless resolver supplies primary position feedback to the drive for tightly regulated velocity and torque.

During continuous duty, the motor can apply 0.5 Nm of stall torque, and it sustains short bursts up to 1.36 Nm when acceleration or load disturbances occur. A torque constant of 0.3 Nm/ARMS links current demand to output torque, which helps with drive sizing and current-loop tuning. Coil characteristics include 14.4 mH of line-to-line inductance and 12.0 ohms of line-to-line resistance; together these values influence electrical time constants, heat dissipation, and the voltage required for rated speed. The single-stack G-winding layout keeps copper loss low, and the motor uses 18-inch flying leads fitted with MS connectors for quick integration. The motor has no holding brake, so static load retention must be managed by the drive or external mechanics, and the housing omits a shaft seal to minimize mechanical drag. The design also excludes a secondary feedback device to save space and weight.

Total mass is limited to 1.4 kg, easing installation on lightweight gantries and collaborative robot joints. Dynamic response is aided by a rotor inertia of 0.042 kgm² × 10⁻³, which balances quick acceleration with smooth speed regulation. Back EMF is characterized by a voltage constant of 0.19 VRMS/rad/sec, which helps with bus voltage selection for the intended speed range. The NEMA 23 frame size, combined with the one-stack length, allows this motor to fit in shallow control cabinets or end-of-arm tool plates while maintaining useful torque density.