Product Description:

The R21HSNA-R1-NS-VS-04 is a servo motor built by Pacific Scientific and supplied within the R Servomotors series. Classified as a compact servo motor, it delivers rotary motion for positioning axes, pick-and-place heads, and other automation stages that demand high acceleration. A 2.0-inch round frame and a 1-inch magnetic stack keep the unit small enough for dense multi-axis platforms, while the standard housing style aligns with typical NEMA-style mounting faces. Its compact envelope suits assemblies where adjacent axes, sensors, and tooling leave little free space around the motor body. The motor arrives without a holding brake, so the load must be secured through drive torque or external locking devices when power is removed.

In continuous operation, the stator develops 0.3 Nm of stall torque, a level that holds the shaft at rated current without overheating. High copper fill and a high-speed winding let the rotor reach its rated velocity of 11,000 rpm, matching applications that need quick indexing rather than high holding force. The cylindrical frame has a 2.0-inch OD, so it fits standard 2-inch motor mounts and tubular actuators. Magnetic flux is supplied by rare-earth samarium-cobalt magnets, a material that produces strong field density in a thin rotor and improves torque density and temperature stability at elevated speeds.

Dynamic events are handled by a peak torque of 0.88 Nm, giving nearly three times the continuous value for rapid acceleration bursts. During those transients, the rotor’s reflected inertia is only 0.01 × 10⁻³ kg·m², minimizing load-to-motor mismatch and easing servo tuning. To protect internal bearings, the shaft passes through a Viton shaft seal that resists chemicals and maintains elasticity at elevated temperatures. Position data is returned through a frameless resolver of size-15 transmitter design, eliminating the need for secondary feedback while preserving absolute orientation under electrical noise. This feedback arrangement supports stable control where long motor leads or nearby power devices can introduce interference.