Product Description:

The PMB31B-20116-02 is a brushless servomotor manufactured by Pacific Scientific as part of the PMB Brushless Servomotors series. Designed for industrial automation, it converts electrical power into precisely controlled rotary motion for indexing tables, pick-and-place heads, and similar duty cycles. The motor is supplied with flying leads equipped with AMP connectors, so integration into existing harnesses is direct. A built-in digital encoder with commutation tracks rotor position, allowing tight velocity and torque loops when the motor is paired with a compatible servo drive.

With a frame that matches the NEMA Size 34 footprint, the motor fits machinery built around that standard mounting pattern. At stall, it delivers 2.1 Nm of continuous torque, ensuring static holding capacity for demanding loads while remaining thermally stable. The feedback device offers 4096 ppr resolution, giving the drive fine position feedback for accurate indexing. Electrical dynamics are influenced by a line-to-line inductance of 19.6 mH, which moderates current ripple and helps the drive perform smooth commutation at high speeds. With a 240 VAC bus, the nominal stall current is 2.7 ARMS, which supports proper drive sizing and cable ampacity selection.

During acceleration, the motor can reach a peak torque of 4.1 Nm, giving nearly double the continuous rating for short bursts such as camming moves. The maximum rated speed of 2900 rpm supports medium-speed spindles and conveyor sections without overspeed errors in the feedback loop. Rotor inertia is only 0.000137 kgm², so rapid directional reversals impose minimal stress on couplings and allow tight servo tuning. Thermal monitoring is handled by a PTC thermistor. The motor also has a square-key shaft, a single-stack lamination with a stack length multiple of 1, and a digital encoder with commutation.