Product Description:

The PMB31B-20100-03 is a brushless servomotor built by Pacific Scientific and offered within the PMB Brushless Servomotors series. As a compact rotary actuator, the unit converts drive current from a servo amplifier into controlled torque and rotary motion, making it suitable for indexing tables, packaging axes, or pick-and-place assemblies in industrial automation. The motor integrates magnetic feedback to support closed-loop regulation and is sized for medium-power tasks where precision and rapid acceleration are required. This arrangement allows the connected drive to monitor rotor behavior continuously during positioning moves and speed changes.

The motor uses a NEMA Size 34 frame, which corresponds to a 3.4-inch square mounting face that aligns with standardized gearboxes and brackets. Continuous torque is available while the windings draw a nominal stall current of 2.7 ARMS, a value used to size a compatible amplifier on a 240 VAC supply. Field wiring is simplified by flying leads with AMP connectors, which allow flexible cable routing without a fixed mating receptacle. Rotor position is monitored by a resolver, so the drive can maintain vector commutation even in electrically noisy environments. Power is transmitted through a square key shaft, providing positive mechanical locking when pulleys or couplings are clamped.

The motor can be ordered with a shaft seal and PTC thermistor package; the seal helps limit contaminant entry at the shaft area, and the thermistor provides over-temperature signaling to the controller. It uses stack length multiple 1, which corresponds to the shortest magnetic stack in this product line and helps keep inertia lower for faster starts and stops. The shorter stack also reduces axial length, which is useful where installation space is limited and fast response is important.