Product Description:

The PMB31B-20214-00 is a brushless servomotor produced by Pacific Scientific within the PMB Brushless Servomotors series. It converts electrical input from a matched drive into controlled torque and speed for indexing tables, pick-and-place axes, or other motion stages in automated equipment. As part of a closed-loop system, the motor supports fast starts, stops, and reversals while helping the axis maintain repeatable position during normal machine cycles. This type of motor is commonly used where compact rotary output and accurate response are required without adding external commutation devices.

The motor frame conforms to NEMA size 34, so the mounting flange and shaft height match standard 3.4-inch square housings used on many machine plates. Position feedback is supplied by an incremental encoder rated at 2048 ppr, giving the drive enough resolution for stable speed regulation and repeatable position updates. At 240 VAC, the nominal stall current is 2.7 ARMS, and drives and cables are sized for this value to prevent overheating during low-speed torque production. Rotor commutation signals are derived from the integrated digital encoder with commutation, eliminating separate Hall devices and simplifying wiring between the motor and the control package. Power and feedback exit the stator through flying leads with MS connectors, allowing quick plug-in to harnesses while still supporting strain relief in high-vibration panels.

Mechanical power is transmitted by a square key on the output shaft, so pulleys or couplings can be locked without relying only on friction during rapid reversals. Because the unit is delivered as a standard motor, no custom windings or seals alter the factory ratings, which keeps the configuration aligned with the base version of the series. The stack length code of 1 denotes the shortest magnetic core available in this frame, which lowers rotor inertia and supports higher acceleration profiles on compact axes.