Product Description:

The 55NM82-100-2 is a direct-current servomotor from Pacific Scientific that belongs to the Low Inertia PMDC Servomotors series. By combining a permanent-magnet field with a low rotor mass, the unit provides rapid torque development for positioning tables, labeling heads, and other medium-power motion axes in automated equipment. Within a closed-loop drive system, the motor converts armature current to rotational output, allowing the controller to regulate speed or holding force as required by the process.

The motor is designed to operate from a 42 V supply and draws a nominal 19.2 A RMS under rated load. Under those conditions, it delivers 439 oz-in (3.10 Nm) of torque while turning at 1420 RPM, producing 461 W of mechanical power at the shaft. When rotor temperature rises to the allowable limit, the windings can withstand a continuous stall load of 474 oz-in (3.35 Nm) without demagnetizing the magnets. A no-load speed of 2310 RPM represents the maximum speed reached when only frictional and iron losses are present. Internal Type 1 convection cooling removes heat, while a terminal resistance of 0.65 Ω and a rotor inductance of 225 µH set the electrical values used by the drive to tune current loops.

Dynamic behavior is governed by a 17.73 V/kRPM back-EMF constant that reflects the voltage generated per unit speed and by a 24.0 oz-in/A torque constant that links armature current to developed torque. Fast current rise is supported by a 0.35 ms electrical time constant, allowing the drive to issue torque commands with minimal delay, while a mechanical time constant of 1.6 ms describes the speed response. The low rotor mass, quantified by a 0.010 oz-in-s² inertia, limits overshoot during reversals, and a thermal path of 0.37 °C/W from rotor to ambient controls temperature rise during cyclic overloads.