Product Description:

The PMB33C-20201-01 is a brushless servomotor produced by Pacific Scientific as part of the PMB Brushless Servomotors series. Designed for closed-loop industrial axes, the unit converts three-phase power from a matched drive into precisely regulated torque and speed. It is used in positioning, feeding, and indexing stations where rapid acceleration and repeatable stopping are required to maintain cycle time and dimensional accuracy. Because torque and speed are regulated by the drive, the motor can follow repeated motion profiles with consistent response under changing load conditions. Its permanent-magnet rotor eliminates brush wear and supports continuous operation without routine brush replacement.

The motor uses a NEMA Size 34 frame, so the mounting face and pilot dimensions fit standard 3.4-inch square motor brackets found on medium-torque machinery. At a 240 VAC bus, the nominal stall current is 3.8 ARMS, which is the continuous phase current required while the shaft remains locked and energized. Rotor position is supplied by a three-phase Hall sensor that provides 120-electrical-degree signals for six-step commutation without an encoder. Power and feedback conductors leave the stator as flying leads with MS connectors, which allows straightforward connection to preselected mating cables. Torque is transmitted through a square key machined into the shaft to help prevent slip at the coupling.

The motor can be ordered with an optional shaft seal, which helps block coolant or dust from moving along the shaft journal during washdown or abrasive service. It also uses a stack length multiple of 3, meaning the active core is built from three lamination sections to increase magnetic capacity without changing the frame size. The seal is useful where contamination may reach the shaft area during normal machine operation. The longer active stack increases torque capability while keeping the external mounting interface consistent with the base motor housing.