Product Description:

The PMB31B-20114-02 is a brushless servomotor manufactured by Pacific Scientific and supplied as part of the PMB Brushless Servomotors series. Designed for closed-loop motion axes, the motor produces controlled torque and velocity so that conveyors, feeders, or light machine tools can follow programmed profiles with minimal following error. Its electromagnetic core is optimized for 240 VAC drives, and the mechanical frame complies with NEMA dimensional standards, so it can replace comparable stepper or DC motors in vector-controlled upgrades.

Its physical envelope corresponds to NEMA Size 34, giving a 3.4-inch square flange that matches common gearbox and bracket patterns. Power conductors exit as flying leads with AMP connectors, permitting quick crimp termination without a mating circular plug and reducing stack length. When the shaft is locked, the winding draws a nominal stall current of 2.7 ARMS at 240 VAC, so the drive output stage can be sized against this value to avoid overcurrent trips during static holding events. Rotor position is reported by an integral encoder that generates 2048 ppr quadrature signals, enabling fine loop tuning and precise interpolation when paired with modern digital drives. Output torque is transmitted through a square key shaft, allowing slip-free coupling to pulleys or helical couplings with standard keyed bores.

Thermal protection and feedback functions are integrated into the motor for closed-loop service. A factory-installed PTC Thermistor is embedded in the stator windings so the drive can reduce current before excessive heat affects insulation. The feedback device is a digital encoder with commutation, and it provides incremental position data along with three commutation tracks, eliminating separate Hall sensors and keeping wiring simple. The motor uses Stack Length Multiple 1, which indicates the shortest lamination stack in the family and favors low inertia for rapid acceleration.