Product Description:

The PMB31B-20114-03 is an AC brushless servo motor built by Pacific Scientific for the PMB Brushless Servomotors series. The unit converts electrical energy into precisely regulated rotary motion, allowing packaging machines, indexing tables, and pick-and-place heads to reach programmed positions with minimal following error. Its integrated feedback device supplies rotor position to the drive, allowing closed-loop control during operation and coordination with PLC-directed axes.

The frame corresponds to NEMA Size 34, establishing a 3.4-inch square mounting face that fits standard brackets without custom adapters. Position feedback is delivered by an incremental encoder rated at 2048 ppr, so each mechanical revolution is divided into 2048 pulses for tight speed and position control. Power and signal wiring exits through flying leads with AMP connectors, which simplifies cable routing in dynamic cable tracks. Rotor orientation data are provided by a digital encoder with commutation, enabling the amplifier to commutate immediately after startup. When supplied from a 240 VAC bus, the motor can sustain a nominal stall current of 2.7 ARMS. A stack length multiple of 1 keeps the active iron short, which helps reduce inertia during rapid acceleration and deceleration.

Torque is transferred through a shaft with a square key, which helps prevent slippage between the rotor and attached pulleys or couplings during bidirectional load changes. The optional shaft seal and PTC thermistor package adds sealing and sends temperature data to the controller for thermal monitoring. The motor uses mounting geometry common to other PMB Brushless Servomotors models in this frame size, which supports straightforward installation on standard machine brackets. These protective features support reliable operation in multi-axis cells that run continuously over long production shifts.