Product Description:

The PMB31B-20100-02 is a brushless servomotor built by Pacific Scientific and supplied within the PMB Brushless Servomotors series. This rotary unit is intended for closed-loop positioning and velocity control in automated machinery where repeatable torque and a compact envelope size are required. By coupling a permanent-magnet rotor with electronic commutation, it converts drive current into controlled mechanical power for indexing tables, pick-and-place actuators, and other motion axes. Its compact rotary design is suited to applications that require quick response during repeated start-stop cycles.

The motor frame conforms to NEMA Size 34, so its mounting face and pilot diameter align with standardized size-34 gearheads and brackets. During worst-case stall at 240 VAC, the winding draws 2.7 ARMS; drives that supply this current can hold the shaft without excessive heating. Rotor position feedback is provided by a resolver, which tolerates high vibration and temperature while delivering sine-cosine signals for precise vector control. Power and signal conductors exit the housing as flying leads with AMP connectors, allowing direct termination to cabinet junction strips. Mechanical coupling is handled by a square key on the shaft, giving positive torque transfer to pulleys or couplings without relying on friction alone. This connection style also simplifies routing where separate motor and feedback plugs are not used.

Thermal protection is integrated through a PTC thermistor embedded in the stator; the device changes resistance sharply near the maximum allowable winding temperature so the drive can reduce current before damage occurs. Dynamic output is influenced by the stack configuration, and this model uses a stack length multiple of 1, the shortest lamination set in the family, prioritizing speed responsiveness over continuous torque. Within the PMB Brushless Servomotors series, that short stack keeps inertia low for rapid acceleration, while the build quality associated with Pacific Scientific manufacturing supports longevity in 24-hour production duty. The unit is classified as a PMB Series brushless servomotor, which helps match it with compatible drive settings.