21-2220D-28678 Pacific Scientific
Wake Industrial LLC is not an authorized distributor of this product.
The Pacific Scientific 21-2220D-28678 is part of the 6410 Stepper Drives series and features a NEMA 23 frame size with a body diameter of 2.25 inches. This stepper drive offers a double-ended shaft configuration with a shaft diameter of 0.25 inches and a step angle of 1.8 degrees. It is designed for operation in temperatures from -20 to 40 degrees Celsius and provides insulation resistance of 100 Megohms at 500Vdc and 25°C.
Internal Product Review
The 21-2220D-28678 is a Pacific Scientific 2-phase stepper motor in a NEMA 23 frame, well suited for precise motion applications. A 1.8° step angle and double-ended shaft configuration support accurate indexing and flexible mechanical integration. Insulation resistance of 100 Megohms @500Vdc and operation from -20 to 40°C make this unit a dependable choice for industrial positioning systems.
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Product Description:
The 21-2220D-28678 is a compact stepper motor released by Pacific Scientific within the 6410 Stepper Drives series. Designed for direct attachment to light mechanical loads, the unit converts step-and-direction pulses into controlled rotary increments that position fixtures, labeling heads, and small actuators in automated equipment. Its role in industrial automation is to deliver repeatable angular displacement without the feedback hardware required by servo systems, allowing open-loop control wherever moderate speeds and accurate indexing are required.
Its NEMA 23 frame provides the flange outline, while a 2.625-inch bolt circle matches standard motor brackets. The cylindrical body measures 2.25 inches (57.15 mm) across, and a ground shaft with a 0.2500-inch (6.35 mm) diameter projects 0.81 inches from the face to accommodate couplings. A rear stub measuring 0.75 inches can support an encoder or hand wheel. Four mounting holes, each measuring 0.200 inches in diameter, pass through the flange for direct fastening. The rotor advances by 1.8° per step, providing 200 discrete positions per revolution. Shaft runout is limited to 0.002 inches to reduce radial error, and the unit operates at ambient temperatures from -20 to 40 °C without forced ventilation.
A two-phase winding connects to common bipolar drives and helps keep torque ripple low. The double-ended shaft allows one end to power the load while the opposite end carries an encoder without an additional coupler. A concentric 1.500-inch (38.1 mm) pilot centers the housing before the flange bolts are tightened. The winding has an insulation resistance of 100 megohms at 500 VDC and 25 °C, limiting leakage when the motor is grounded to a metal frame. The front shaft projection supports direct connection to compact pulleys, gears, or flexible couplings used in automated motion assemblies. The rear shaft extension also permits manual positioning when the connected mechanism must be adjusted while power is removed.
