Product Description:

The PMB31D-20200-03 is a brushless AC servomotor manufactured by Pacific Scientific in the PMB Brushless Servomotors series. It is intended for closed-loop motion tasks in industrial automation where repeatable position and speed control are required, such as pick-and-place heads or small conveyor sections. By pairing permanent magnets in the rotor with stator windings driven by a servo amplifier, the motor delivers precise torque that can be regulated in real time by the system controller. This type of motor is well suited to machines that need frequent starts, stops, and direction changes without losing servo accuracy.

This model is built on a NEMA Size 34 frame, giving it mounting dimensions compatible with many mid-frame gearheads and linear stages. A nominal stall current of 5.4 ARMS at 240 VAC indicates the continuous current the drive must supply when the shaft is locked. That value is important when matching the motor to an amplifier because the drive must support the required current without overheating. Position feedback is provided by a resolver, allowing shaft angle detection even in electrically noisy environments. Power and feedback exit through flying leads with MS connectors, which can simplify wiring where only short pigtails need to pass through the cabinet wall. Torque is transferred through a square-key shaft, which helps prevent slippage during bidirectional load reversals common in indexing cycles.

The motor is supplied with a shaft seal and PTC thermistor. The seal helps limit ingress at the front bearing, and the thermistor provides a temperature signal that can be used for overload protection by the connected drive. It uses a stack length multiple of 1, which is the shortest stator stack in this series and helps reduce inertia for faster acceleration. The shorter active length supports responsive motion on light to moderate loads. This compact motor body is useful where available installation length is limited.