Product Description:

The PMB31D-20216-03 is a brushless servomotor produced by Pacific Scientific as part of the PMB Brushless Servomotors series. In automated assembly cells, packaging stations, and semiconductor tooling, this motor supplies commanded torque and speed while maintaining tight position control through integrated electronic feedback. Its brushless architecture minimizes maintenance and allows continuous cycling on 240 V servo amplifiers common to modern motion controllers. The housing and rotor are balanced for rapid acceleration so that high-throughput machines can achieve consistent repeatability across thousands of cycles. This operating style suits axes that must start, stop, and reverse direction frequently without sacrificing smooth motion.

Its feedback device offers 4096 ppr resolution, so each mechanical revolution is divided into 4096 position increments that the drive can detect for fine motion profiling. The frame matches the NEMA Size 34 standard, providing a 3.4-inch square mounting face that aligns with many gearbox and bracket layouts. Under maximum 240 V operation, the winding can deliver a nominal stall current of 5.4 ARMS, which indicates the continuous torque level before temperature rise exceeds acceptable limits. Power and Hall signals exit the stator on flying leads with MS connectors, simplifying cable routing through articulated carriers. Rotor position is reported by a digital encoder with commutation, so the same sensor supplies both incremental counts and phase alignment data to the drive. Output torque is transferred through a square key on the shaft, which helps prevent slip between the motor and the attached load.

A factory-installed shaft seal and PTC thermistor help keep contaminants out and alert the amplifier to overheating, so protective action can begin before damage occurs. The magnetic core uses a stack length multiple of 1, which is the shortest lamination stack in the series. This layout gives the motor lower inertia for faster starts and stops, which is useful on axes with frequent short moves and repeated speed changes.