Product Description:

The PMB31B-20216-02 belongs to the PMB Brushless Servomotors series from Pacific Scientific. It is an AC servomotor intended for closed-loop motion axes in automated machinery, where precise torque and speed regulation are required for positioning tasks. Its combination of encoder feedback and a low inertia rotor helps the drive respond quickly to command changes in robotics, pick-and-place heads, and indexing tables. That operating profile is useful in applications that start and stop frequently, because the motor can follow rapid changes in speed and position without excessive lag.

The motor housing corresponds to NEMA Size 34, so it mounts directly to gearboxes and brackets that follow that dimensional pattern. Under locked-rotor conditions at 240 VAC, its windings can draw up to 2.7 ARMS, which means the connected drive must support that current without nuisance trips. Power and encoder terminations exit through Flying leads with MS connectors, which simplifies connection in cabinet or gantry installations. Rotor position is reported by a Digital encoder with commutation, and each revolution is subdivided into 4096 ppr for smooth velocity control and accurate positional feedback. Because commutation and position data come from the same feedback device, wiring remains consolidated and the control loop receives consistent rotor angle information across the speed range.

Internal thermal safeguarding is provided by a PTC thermistor embedded in the stator, enabling the drive to reduce output or shut down before the coil insulation overheats. Mechanical output is transferred through a square key on the shaft, which helps prevent slip when peak torque is transmitted to couplings or pulleys. The lamination stack uses a stack length multiple of 1, which keeps the motor compact while supporting the torque expected from this frame size. The embedded sensor also gives the control system a direct indication of winding temperature rise during repeated acceleration and dwell cycles.