Product Description:

The PMB31B-20200-01 brushless servomotor is built by Pacific Scientific and is part of the PMB Brushless Servomotors series. It converts three-phase electrical power into controlled mechanical output for pick-and-place heads, gantry drives, and metering pumps where precise position or velocity control is required. A permanent-magnet rotor, electronic commutation, and a compact frame allow the motor to mount close to the load, which helps reduce coupling compliance and supports high cycle rates in automated equipment.

The frame follows the NEMA Size 34 standard, so its 3.4-inch square face and bolt pattern fit common industrial brackets. Power and feedback exit through flying leads with MS connectors, which provide pre-terminated connections for compatible drive and control wiring. Position feedback is supplied by a resolver, an analog transducer that withstands heat and vibration while providing rotor angle information for commutation. The nominal stall current is 2.7 ARMS at 240 V AC maximum, allowing compatible amplifiers to deliver continuous torque without overheating. Mechanical energy is transferred through a square key shaft, which helps gears, pulleys, or couplings resist rotational slip during rapid acceleration.

To reduce lubricant loss and limit particle entry, the motor can be supplied with a shaft seal that forms a dynamic barrier at the output journal. This feature improves resistance to dust and oil mist in dirty operating areas. The motor uses a stack length multiple of 1, which keeps the magnetic section compact and helps limit mass and inertia for faster response. That layout supports a single-stack design, which shortens overall body length and keeps the thermal path direct. The compact format also helps the motor fit installations where space around the driven axis is limited.