Product Description:

The P21NRXB-JNF-NS-00 is a two-phase stepper motor manufactured by Pacific Scientific as part of the POWERMAX II P Motors series. It accepts pulse and direction commands from motion controllers and converts them into accurate shaft increments, making it useful in indexing tables, light gantries, and metering equipment. A low-inertia rotor and single-ended shaft help the motor start and stop quickly, while a NEMA mounting flange simplifies integration with existing brackets and gearheads. It is well suited to compact automation assemblies where predictable indexing matters more than servo-style closed-loop performance.

This model occupies the NEMA 23 frame envelope, giving it a 57 mm square body that fits common drive layouts. Each electrical step advances the shaft by 1.8 degrees, so a full revolution requires 200 steps. That step angle also works well with microstepping drives that divide commanded motion into smaller increments for smoother rotation. The windings are insulated to Class B (130 °C), and the motor can operate across an ambient range of −20 °C to +40 °C. Leadwires exit the receptacle, allowing straightforward series or parallel hookup to bipolar drives rated up to the 340 Vdc insulation voltage.

Load capacity reflects the motor’s 52.3 mm length and single-stack design: axial force should not exceed 13 lb, while radial side loads are limited to 20 lb at the reference shaft extension. The ground steel shaft is sized at 6.35 mm diameter with a 12.7 mm usable flat for set-screw couplings, which helps prevent slip during torque transfer. Positional repeatability is maintained within ±1.5 % of the nominal step, aided by the low rotor inertia that helps limit overshoot during rapid indexing. These load limits should be considered when pairing the motor with pulleys, couplings, or lead screws so bearing stress and shaft deflection remain under control.