Product Description:

The PMB31D-20200-01 is a brushless servo motor manufactured by Pacific Scientific and supplied within the PMB Brushless Servomotors series. It is intended for closed-loop motion tasks where accurate speed regulation and rapid positioning improve throughput in automated equipment such as pick-and-place stations, conveyors, and light machine-tool axes. Its brushless design supports smooth commutation with a compatible servo drive and helps maintain repeatable motion during frequent start-stop cycles. That operating profile suits machinery that must accelerate quickly, settle accurately, and repeat the same move over long production runs.

The motor uses a NEMA Size 34 frame, so its mounting face and pilot diameter match standard 3.4-inch flange hardware commonly found in US machinery. Power and feedback conductors exit through flying leads with MS connectors, allowing quick mate-and-lock installation without separate terminal blocks. On a 240 VAC bus, it can withstand a nominal stall current of 5.4 ARMS, which the drive must supply to produce rated static torque without losing synchronism. Rotor position is detected by a resolver, providing analog sine-cosine signals that remain reliable in high temperatures and electrically noisy settings. Mechanical output is transferred through a shaft machined for a square key, giving positive torque transmission to pulleys or couplings without slippage.

For environments that require contamination control, the motor has a shaft seal, which limits ingress along the output journal when the unit is mounted to an unsealed gearbox or housing. The stack length code of 1 indicates the shortest magnetic core in the series, which reduces mass and rotor inertia for faster acceleration while still supporting moderate torque demand. The shorter package can also help when axis spacing is tight or when moving mass needs to stay low for responsive indexing. Compact servo axes with limited mounting space can benefit from the shorter package and the sealed output end.