Product Description:

The 4VM82-220-7 is a permanent-magnet DC servomotor produced by Pacific Scientific for the Low Inertia PMDC Servomotors series. Built for industrial automation, the unit converts low-voltage DC power into precisely regulated torque and speed, providing a compact drive source for indexing tables, laboratory pipettors, and lightweight conveyors. Its low rotor inertia supports close tracking of command profiles, allowing motion controllers to produce rapid acceleration without excessive setpoint overshoot.

Under continuous load, the motor provides a continuous stall torque of 2.26 N·m while drawing current from a 42 V DC bus. At that voltage, it reaches a rated shaft speed of 1500 rpm and delivers a mechanical output of 350 W, balancing speed and torque for medium-power axes. Rapid current rise is supported by an electrical time constant of 0.34 ms, allowing the drive to modulate current quickly and improve low-speed servo stiffness. Terminal resistance at 25 °C is 0.50 Ω, which limits inrush current and supports appropriate drive sizing. The motor can reach 2340 rpm without an external load, providing additional speed range for regulated processes.

The motor has a mechanical time constant of 1.5 ms, so the rotor reaches 63% of a commanded speed step shortly after the armature current rises. Generated voltage during rotation follows a back-EMF constant of 11.1 V/krpm, providing predictable values for velocity observers and regenerative braking calculations. Each ampere of armature current produces a torque constant of 0.106 N·m/A, allowing torque to scale linearly with commanded current and simplifying control-loop tuning. The assembly has a mass of 10 lb, permitting installation on moving carriages or articulated joints without adding excessive mechanical load.