Product Description:

The PMB31D-20201-02 is a brushless servomotor produced by Pacific Scientific within the PMB Brushless Servomotors series. Intended for industrial automation, the unit converts electrical power into controlled rotary motion so drives can maintain precise velocity, torque, and position on packaging, material-handling, and assembly equipment. It operates from matched servo drives that supply three-phase AC and closes the loop through commutation signals. A thermally protected stator supports extended duty cycles in compact motion axes where heat must be monitored closely. This arrangement helps the motor respond quickly to command changes while maintaining controlled motion during repeated acceleration and stopping cycles.

Its frame is classified as NEMA Size 34, which gives the motor a standardized 3.4-inch square face for common gearbox and bracket patterns. During locked-rotor thermal testing at 240 VAC, the motor draws 5.4 ARMS, and this nominal stall current value is used to size compatible drivers and fuses. Three integrated Hall sensors relay commutation edges to the drive so phase sequencing remains accurate at low speed and during startup. Power and feedback leave the stator through flying leads with MS connectors, which supports straightforward cable routing in enclosed machinery. A PTC thermistor embedded in the windings changes resistance sharply near the safe temperature limit and can trigger an external shutdown circuit.

For mechanical coupling, the shaft uses a square key that transfers torque to pulleys or couplings while helping prevent slip under transient loads. The stack length multiple of 1 indicates a single magnetic lamination stack, which balances torque output with a compact axial envelope for installations with limited depth. This shorter magnetic stack helps the motor fit tightly spaced axes without adding unnecessary length to the drive train. The keyed shaft format also suits applications that need positive torque transfer between the motor and the driven load. These features support stable operation in compact automation systems that run repeated start-and-stop motion profiles.