Product Description:

The 33VM82-020-15 is a permanent-magnet DC servomotor produced by Pacific Scientific within the Low Inertia PMDC Servomotors series. Its low rotor inertia makes it suitable for tight position loops where rapid direction changes are frequent. By integrating a tachometer on the non-drive end, the assembly supplies real-time velocity data to the controller. Within an automated cell, the motor converts armature current into proportional torque, enabling precise indexing, tension control, or speed-following tasks without mechanical gearboxes. That behavior supports applications that reverse often or must follow rapidly changing commands.

The motor’s magnetic circuit uses Alnico V-7 magnets, which provide stable flux density and resist demagnetization during peak current surges. Because the frame uses no forced-air cooling, heat is carried away only by conduction and natural convection, which matters when the motor is installed in confined cabinets. This cooling method avoids the need for an external blower and keeps the package simple. For velocity feedback, the integral tachometer delivers 2.5 V/kRPM, so the drive can derive speed through a simple voltage measurement. The generator section has an armature resistance of 50 ohms, which limits current draw into the speed loop, and its rotor diameter of 2.765 in sets the overall feedback envelope size.

Electrical ripple and tachometer size also affect control behavior. The generated signal keeps speed regulation steady because electrical ripple is held to 1.5% p-p, minimizing velocity dithering at low speeds. This is especially useful in analog speed loops, where ripple in the feedback signal can appear as unwanted speed variation. The tachometer section has an overall length of 2.062 in, allowing the motor-tach assembly to fit shallow machine frames without spacer plates. A standard tachometer construction is used, so the motor works with conventional two-wire velocity loops used across multiple drive families.