Product Description:

The PMB31B-20101-03 is a brushless servo motor manufactured by Pacific Scientific within the PMB Brushless Servomotors series. It is intended for closed-loop position and velocity tasks in automated machinery such as small gantries, feeders, and material-handling stations. By combining electronic commutation with permanent-magnet torque production, the motor delivers repeatable motion without the brush wear associated with DC designs and can be mounted directly to gearheads or belt stages. This layout is useful on compact axes that require controlled acceleration and stable low-speed operation.

The frame follows the NEMA Size 34 standard, so the flange and pilot diameters match common U.S. mounting plates. At 240 VAC, its nominal stall current is 2.7 ARMS, indicating the continuous phase current a compatible drive must deliver while holding a load at standstill. A stack length multiple of 1 indicates that this model uses the shortest magnetic stack in the family, which helps keep torque moderate and inertia low. Rotor position feedback comes from a Hall sensor, giving six-step commutation signals that suit mid-range motion controllers. Power, feedback, and protective earth exit the housing through flying leads with AMP connectors, allowing field termination without opening a terminal box.

An output shaft machined with a square key transmits torque to couplings while helping prevent slippage during frequent start-stop cycles. Factory-installed additions of a shaft seal and a PTC thermistor help protect the bearings against fluid ingress and alert the drive when winding temperature reaches the trip level. These features support operation in mildly contaminated areas or in installations with limited thermal margin. The motor is suited to indexing tables, conveyors, and pick-and-place axes where frame size is restricted and steady stall torque with basic electronic feedback is needed.