Product Description:

The PMB31B-00116-02 brushless servo motor is built by Pacific Scientific and is part of the PMB Brushless Servomotors series. It is a rotary actuator intended for servo loops in automated assembly stations, pick-and-place heads, and indexing tables. By coupling a permanent-magnet rotor with electronic commutation, the motor supplies continuous torque without brush maintenance and supports repeatable positioning in compact machinery layouts. In typical use, it bolts directly to gear reductions or belt drives and translates drive current from a matched amplifier into regulated shaft motion.

Mechanical dimensions follow the NEMA Size 34 frame convention, so mounting holes align with standard 3.4-inch square flanges. A high-resolution feedback loop is delivered by the integral encoder, which outputs 4096 ppr and allows the controller to command sub-degree positioning. Phase windings draw up to 2.7 ARMS of stall current at 240 VAC, which sets amplifier current capacity and thermal loading during low-speed hold. Power and feedback conductors exit the housing as flying leads with AMP connectors, which helps when fixed cables are not practical. Commutation data is provided by a digital encoder with commutation, which removes the need for separate Hall sensors and reduces wiring complexity.

Application flexibility is increased by the shaft’s flat profile, which provides a positive drive surface for couplings or pulleys without requiring a keyed hub. Internal temperature rise is monitored by a PTC thermistor; this element changes resistance sharply near the insulation limit so the drive can reduce current before damage occurs. The electromagnetic section uses a stack length multiple of 1, which gives moderate inertia for rapid acceleration cycles. Motors in the PMB Brushless Servomotors family share the same electrical constants, so units in the line maintain consistent current and back-EMF behavior across multi-axis platforms.