Product Description:

The P21NRXB-LSS-NS-05 is a two-phase hybrid stepper motor produced by Pacific Scientific in the POWERMAX II P Motors series. Designed for open-loop positioning and speed duties inside automated machinery, it converts discrete pulse commands from a drive into precise angular motion without internal feedback. A NEMA 23 frame and standard construction allow it to fit common motion axes, while its single-stack rotor supplies consistent torque for light-to-medium load points.

Holding torque reaches 0.79 N·m, enabling the shaft to resist external loads between commanded moves, while detent torque of 0.03 N·m is the residual magnetic lock when the phases are not energized. Each full step spans 1.8°, so a complete revolution is divided into 200 steps per revolution, and intrinsic step accuracy remains within ±1.5%. The windings draw 4.6 A per phase at stall, and their electrical constants of 1.1 mH inductance and 0.64 Ω resistance affect current rise time and drive voltage selection. Two phases and the B-type winding pattern are wound inside a single stator stack, producing the flux that drives the standard rotor.

The motor has a motor-to-ambient thermal rating of 5.5 °C/W, and with this value the housing should remain below the 95 °C surface limit when the environment stays within the -20 °C to +40 °C operating range. Windings use Class B insulation rated for 130 °C and pass a dielectric withstand of 500 VDC for 1 minute, while insulation resistance measures 100 MΩ at 500 V. The enclosure is rated IP23, which allows ventilation while helping block fingers and falling spray up to 60° from vertical. A 340 VDC insulation voltage rating supports higher-speed drives, and the NEMA mounting face, regular leadwires with a receptacle, and lack of an encoder simplify installation in panel interiors where external feedback is unnecessary.