Product Description:

The 33VM62-220-8 is a low-inertia permanent-magnet DC servomotor manufactured by Pacific Scientific within the Low Inertia PMDC Servomotors series. Designed for positioning and speed-control loops, this motor converts armature current into mechanical torque with minimal rotational inertia, allowing tight following of command profiles in pick-and-place tables, indexers, and light gantry axes. Integrated feedback devices deliver velocity and incremental position data directly to drives or PLC motion cards, supporting closed-loop control schemes common in industrial automation.

In the electromagnetic circuit, the field flux is produced by Alnico V-7 magnets that maintain stable remanence, so torque constants stay predictable. The armature winding is a medium torque-constant design, balancing amperage demand with speed range for general-purpose servo axes. Incremental feedback originates from an optical encoder powered at 5 VDC ±5% at 150 mA; this supply is typical for motion drives and avoids separate regulators. The codewheel can be read at carrier rates up to 100 kHz, supporting high linear velocities without loss of edge fidelity. Between the rotor and stator, a 0.005 in air gap is maintained; the tight clearance improves magnetic coupling yet requires precise bearing alignment. For transient moves, the armature can deliver up to 5 times rated torque, allowing fast acceleration of low-inertia loads.

Light passing through the encoder disk is generated by a LED, ensuring consistent signal amplitude for the square, dual-channel, zero-index pattern that the controller interprets for incremental position tracking. Commutation relies on carbon brushes, a choice that simplifies drive electronics but introduces scheduled maintenance for brush wear. The motor’s hollow rotor construction further reduces rotating mass, complementing its low-inertia profile, while a shaft diameter of 0.344 to 0.406 in offers compatibility with standard couplings. An analog tachometer is built in for velocity feedback when legacy drives require a voltage proportional to speed. The unit operates without forced-air cooling and depends on natural convection to dissipate heat generated during duty cycles.