Product Description:

The PMB31D-00116-02 is a brushless servomotor manufactured by Pacific Scientific for the PMB Brushless Servomotors series. It is built for closed-loop control of torque, velocity, and position on packaging equipment, robotic joints, and material-handling systems. By combining a permanent-magnet rotor with electronic commutation, the unit minimizes maintenance and supports accurate, repeatable motion under continuous industrial duty. Because there are no brushes to wear, routine service is reduced and commutation accuracy remains stable over long operating periods.

The motor frame is sized at NEMA Size 34, which provides a 3.4-inch square mounting footprint that matches many standard brackets and gearbox interfaces. Rotor position is monitored by a 4096 ppr incremental encoder, allowing the control system to track shaft movement with fine resolution during positioning tasks. Continuous torque at stall is supported by a nominal winding current of 5.4 ARMS when driven from a 240 V AC bus, so the drive must be able to supply that current without saturation. Feedback and phase alignment are handled by a digital encoder with commutation, which eliminates Hall sensors and simplifies the feedback arrangement. Thermal protection is provided through an integrated PTC thermistor that sharply increases resistance as motor temperature rises.

Connection to the cabinet is made through flying leads with AMP connectors, so the motor can be wired without a separate on-motor plug assembly and the harness can be routed directly into cable carriers or enclosed panels. A machined flat on the shaft helps transmit torque to pulleys or pinions while reducing the chance of slip during rapid load changes. The design uses a stack length multiple of 1, which corresponds to the shortest lamination stack in this series and favors low rotor inertia in compact motion axes. This shorter stack can be useful where available mounting depth is limited and fast acceleration is required.