Product Description:

The PMB31B-00101-02 is a brushless servomotor built by Pacific Scientific for the PMB Brushless Servomotors series. As a permanent-magnet device, it converts electrical energy into controlled rotary motion, allowing drive amplifiers to maintain accurate velocity and torque in pick-and-place stations, indexing tables, and similar automation axes. Its brushless design supports repeatable motion during frequent start-stop cycles and avoids the wear associated with mechanical commutation. This motor suits applications that need closed-loop performance in limited space, because its compact frame and integrated feedback simplify mounting inside machine frames and electrical cabinets.

Mechanically, the motor uses the NEMA Size 34 mounting interface, so it aligns with standard 3.4-inch square faceplates and mates directly to gearboxes or brackets without adapter rings. Continuous torque is sustained at the rated winding point because the coils reach nominal stall at 2.7 ARMS, an important value for sizing the servo drive current loop. Power and feedback are routed through flying leads with AMP connectors, eliminating fixed plugs and making cable harnesses easier to thread through tight machine channels. Rotor position for commutation is provided by an embedded Hall sensor, enabling six-step and sinusoidal control modes. This arrangement supports amplifiers that rely on discrete commutation signals during startup and low-speed operation. The output shaft is machined with a flat, giving set screws a positive seat and helping prevent slip under transient torque loads.

Thermal protection is handled by the integrated PTC thermistor, which rises sharply in resistance near the critical winding temperature and prompts the amplifier to cut current before insulation damage occurs. The motor uses a stack length multiple of 1, which is the shortest lamination stack offered for this motor line and helps keep rotor inertia low for fast acceleration on light moving loads. Its compact dimensions make it suitable for small slides, feeders, and other axes where installation space is restricted. The motor also includes an integrated sensor package that supports stable commutation feedback without adding external hardware at the machine axis.