Product Description:

The S21GSAA-RNNM-02 is a 6-pole neodymium-magnet brushless servo motor made by Pacific Scientific for the S Brushless Motors series. It provides precise rotary motion for pick-and-place modules, indexers, and small tool carriages in automated equipment where repeatable positioning and responsive speed control are required. A frameless size 21 resolver mounted on the shaft supplies the primary position signal to the drive. The motor does not include a secondary feedback device, which keeps wiring simpler and reduces the number of connected signal channels.

At stall, the motor can deliver 0.5 Nm of continuous torque for steady loads without excessive heating. For short acceleration demands, it can produce up to 1.36 Nm of peak torque, giving the axis extra momentary force to overcome inertia. A torque constant of 0.3 Nm/ARMS links phase current to produced torque, which helps the drive translate current commands into motion output. The phase inductance of 14.4 mH influences current rise, while the line-to-line resistance of 12.0 ohms contributes to copper losses and thermal behavior. Its back EMF coefficient is 0.19 VRMS/rad/sec, so generated voltage increases with speed and should be considered when matching the motor to the drive. Winding code G identifies the conductor gauge and turn count used in this version.

The rotor inertia is 0.042 × 10⁻³ kg·m², which supports quick speed changes on compact servo axes. Overall mass is 1.4 kg, helping reduce the load placed on lightweight stages and brackets. The housing uses a NEMA 23 footprint for direct mounting on 57 mm face brackets. A normally engaged brake rated at 24 V DC holds position when power is removed. The motor has no shaft seal, so the shaft opening should be protected from liquid contamination. It uses a single magnetic stack to keep axial length short, and the power and feedback leads terminate in a motor-mounted MS connector.