Product Description:

The PMB31D-20101-02 is a brushless servomotor built by Pacific Scientific and supplied within the PMB Brushless Servomotors series. In automated machinery, it converts controlled electrical energy from a matched drive into precision rotary motion, allowing position and velocity loops to be closed tightly on pick-and-place gantries, indexing tables, or small conveyors. Its electromagnetic design supports rapid acceleration while delivering repeatable torque, making the unit suitable for axes where consistent responsiveness is required across the production cycle.

The frame falls under NEMA Size 34, giving a 3.4-inch square mounting face that matches standardized motor brackets. When supplied at 240 Vac, the winding draws a nominal stall current of 5.4 ARMS, so the paired amplifier must be rated for that continuous load to avoid current limiting. Power, Hall, and thermal leads exit as flying leads with AMP connectors, reducing the depth required inside a machine enclosure. Rotor feedback is supplied by a Hall sensor, supporting trapezoidal commutation and allowing a fast initial position estimate after power-up. Torque passes to external components through a shaft machined with a square key, which locks hubs or pulleys without relying on friction alone for torque transmission.

The windings include a PTC thermistor that changes resistance sharply near the maximum temperature, giving the drive a discrete signal to initiate a controlled shutdown rather than relying solely on estimated thermal models. The stator stack is built with a stack length multiple of 1, the shortest available option in the family. This limits rotor inertia for faster settling while also trimming motor length, which is useful when tooling envelopes are tight.