Product Description:

The PMB21B-Y0Y00-11 is a brushless servomotor built by Pacific Scientific for the PMB Brushless Servomotors series. Its NEMA size 23 frame allows direct installation on compact machinery where limited space meets moderate load demands. When paired with a resolver feedback loop, it supplies closed-loop motion and precise shaft position for pick-and-place devices, indexing tables, miniature conveyor drives, and similar compact automation systems.

The motor delivers a continuous stall torque of 0.64 Nm, sufficient to hold loads at standstill without thermal overload, while a peak capability of 1.92 Nm supports short acceleration bursts. A nominal stall current of 2.7 ARMS at a 240 VAC bus guides drive sizing and fuse selection. Its electromagnetic conversion is characterized by a torque constant of 0.34 Nm/ARMS, linking commanded phase current to output torque, and a back-EMF voltage constant of 0.22 VRMS/rad/s that the drive must match for stable velocity regulation. Static friction is rated at 0.034 Nm, so low-speed positioning requires minimal additional drive torque. The rotor inertia of 0.023×10⁻³ kg·m² helps the axis start and stop quickly, and a stack length multiple of 1 indicates the shortest magnetic stack in the PMB family.

Electrical dynamics stem from a line-to-line inductance of 4.0 mH that filters phase current ripple and a phase resistance of 6.0 ohms that limits copper losses under continuous duty. Thermal design is summarized by a housing-to-ambient thermal resistance of 1.39 °C/W; when combined with the thermal time constant of 22 min, it shows that the motor can tolerate transient overload periods before reaching steady-state temperature. The resolver sensor supports accurate position feedback across the speed range, helping maintain tight servo loops with these electrical and thermal characteristics.