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AW28HS Series — 28mm Stepper Motor with Precision Planetary Gearbox
The AW28HS series pairs Apexwell's NEMA 11 (28mm), 1.8° hybrid stepper motor with an HPR28 precision planetary gearbox, offering motor holding torque from 0.07 N·m to 0.13 N·m and rated output torque up to 6 N·m after reduction. With three available gear-train stages and reduction ratios from 4:1 to 200:1, backlash is held to ≤15 arcmin at no load — roughly an order of magnitude tighter than Apexwell's standard-tolerance planetary gearmotors — making this series the precision-positioning option on the 28mm frame.
Shared Specifications (all models)
| Parameter | Value |
|---|---|
| Step Angle | 1.8° |
| Lead Wires | 4 (bipolar) |
| Gear Material | Metal |
| Output Bearing | Ball bearings |
| Max Radial Load | ≤10 kgf |
| Max Shaft Axial Load | ≤5 kgf |
| Backlash (no load) | ≤15 arcmin |
| Noise | ≤55 dB |
Motor Model Comparison
| Model | Body Length | Phase Current | Phase Resistance | Phase Inductance | Holding Torque | Rotor Inertia | Mass |
|---|---|---|---|---|---|---|---|
| AW28HS30-1004A | 30 mm | 1.0 A | 2.9 Ω | 1.9 mH | 0.07 N·m | 8.5 g·cm² | 0.09 kg |
| AW28HSA33-0804A | 33 mm | 0.8 A | 5.3 Ω | 3.3 mH | 0.08 N·m | 9.3 g·cm² | 0.10 kg |
| AW28HS40-0704A | 40 mm | 0.7 A | 6.5 Ω | 6.0 mH | 0.12 N·m | 13.5 g·cm² | 0.12 kg |
| AW28HSA45-0804A | 45 mm | 0.8 A | 7.8 Ω | 5.4 mH | 0.13 N·m | 15.0 g·cm² | 0.15 kg |
| AW28HSA48-0804A | 48 mm | 0.8 A | 8.6 Ω | 6.7 mH | 0.13 N·m | 17.2 g·cm² | 0.20 kg |
| AW28HS50-0674A | 50 mm | 0.67 A | 8.4 Ω | 5.6 mH | 0.12 N·m | 18.9 g·cm² | 0.21 kg |
HPR28 Precision Planetary Gearbox Specifications
| Parameter | 1-Stage | 2-Stage | 3-Stage |
|---|---|---|---|
| Reduction Ratio | 4, 5, 7, 10 | 16, 20, 25, 28, 35, 40, 50, 70 | 64, 80, 100, 125, 140, 175, 200 |
| Gearbox Length (L1) | 33 mm | 41.5 mm | 50 mm |
| Rated Output Torque | 1–2 N·m | 3–4 N·m | 6 N·m |
| Transmission Efficiency | 96% | 94% | 90% |
| Weight | 96 g | 130 g | 160 g |
Momentary torque moment is rated at two times the rated allowable load across all three stages — a more conservative overload margin than Apexwell's standard planetary line, in keeping with the gearbox's precision tolerancing. 19 reduction ratios are available in total (4 to 200:1).
Typical Applications
With backlash held to ≤15 arcmin and reduction ratios up to 200:1 on a 28mm footprint, the AW28HS precision series fits semiconductor handling equipment, optical and photonics alignment stages, medical and surgical robotics, and other high-precision positioning tasks where standard-tolerance planetary gearing (typically several degrees of backlash) isn't accurate enough.
Why Choose the AW28HS Precision Gearmotor
Backlash of ≤15 arcmin — roughly 10x tighter than Apexwell's standard M28GXR planetary line on the same motor platform — makes this series suitable for applications where positioning repeatability matters more than cost. Nineteen reduction ratios across three gear-train stages let one motor selection be tuned across a wide speed/torque window without changing the mounting footprint, and noise is held to ≤55 dB for use in lab and clean-room environments. For applications where backlash tolerance is less critical, Apexwell's standard planetary gearmotor line on the same frame offers a lower-cost alternative. Custom shaft configurations and encoder feedback are available on request.
We can customize the electrical parameters of the motor and geometric dimensions such as the motor output shaft size according to customer requirements. Accessories including pulleys, eccentric gearboxes, planetary gearboxes and encoders can also be added. For more products and detailed specifications, please download the product catalog from the Download Center.
