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AW42HS Series — NEMA 17 Stepper Motor with Precision Planetary Gearbox & Brake
The AW42HS series pairs Apexwell's NEMA 17 (42mm), 1.8° hybrid stepper motor with an HP42 precision planetary gearbox and an integrated holding brake in one assembly, combining ≤15 arcmin backlash with a locked shaft when power is removed. Motor holding torque scales from 0.16 N·m to 0.75 N·m across six body lengths, gearbox output torque reaches up to 12 N·m, and each model is available in either 4-wire (bipolar) or 6-wire (center-tap) configuration.
Shared Specifications (all models)
| Parameter | Value |
|---|---|
| Step Angle | 1.8° |
| Step Accuracy | ±5% |
| Lead Wire Configuration | 4-wire (bipolar) or 6-wire (center-tap) |
| Gear Material | Metal |
| Backlash (no load) | ≤15 arcmin |
| Noise | ≤55 dB |
| Brake Type | Spring-applied holding brake |
| Insulation Class | Class B (130°C) |
| Temperature Rise | 50K Max |
| Ambient Temperature | -20°C to +50°C |
| Insulation Resistance | ≥100 MΩ (500 VDC) |
| Dielectric Strength | 500 VAC, 1 minute |
Motor Model Comparison
| Model | Body Length | Phase Current | Phase Resistance | Phase Inductance | Holding Torque | Rotor Inertia | Mass |
|---|---|---|---|---|---|---|---|
| AW42HS20-1004A | 20 mm | 1.0 A | 3.6 Ω | 4.1 mH | 0.16 N·m | 26.0 g·cm² | 0.10 kg |
| AW42HS28-1204A | 28 mm | 1.2 A | 3.0 Ω | 7.5 mH | 0.13 N·m | 28.7 g·cm² | 0.17 kg |
| AW42HS34-1304A | 34 mm | 1.3 A | 2.4 Ω | 2.8 mH | 0.24 N·m | 41.8 g·cm² | 0.22 kg |
| AW42HS40-1704A | 40 mm | 1.7 A | 2.2 Ω | 3.8 mH | 0.40 N·m | 58.5 g·cm² | 0.28 kg |
| AW42HS48-1704A | 48 mm | 1.7 A | 3.1 Ω | 5.0 mH | 0.55 N·m | 79.5 g·cm² | 0.35 kg |
| AW42HS60-1704A | 60 mm | 1.7 A | 2.1 Ω | 6.2 mH | 0.75 N·m | 116.0 g·cm² | 0.48 kg |
HP42 Precision Planetary Gearbox Specifications
| Parameter | 1-Stage | 2-Stage |
|---|---|---|
| Reduction Ratio | 3, 4, 5, 7, 10 | 16, 20, 25, 28, 30, 35, 40, 50, 70, 100 |
| Gearbox Length (L1) | 35 mm (square) / 40 mm (round) | 46 mm (square) / 51 mm (round) |
| Rated Output Torque | 5–9 N·m | 5–12 N·m |
| Transmission Efficiency | 96% | 94% |
| Weight | 250 g | 360 g |
Momentary torque moment is rated at two times the rated allowable load across both stages. 15 reduction ratios are available in total (3 to 100:1), with a choice of square or round output flange on the same reducer length.
Brake Specifications
| Parameter | Value |
|---|---|
| Static Friction Torque | 0.24 N·m |
| Rated Voltage | DC 24V ±10% |
| Rated Power | 5.0 W |
| Max Speed | 5,000 rpm |
| Response Time | 50 ms |
| Insulation Class | Class B |
The brake holds the motor shaft when de-energized and releases when 24VDC is applied, independent of the motor phase windings and the gearbox.
Wiring
Each AW42HS motor is available in either 4-wire (bipolar) or 6-wire (center-tap) configuration, so it can drop into either a bipolar or unipolar driver setup without a different motor SKU. The brake coil is wired and powered separately.
Typical Applications
With ≤15 arcmin backlash, gearbox torque up to 12 N·m, and a holding brake that locks the shaft on power loss, the AW42HS series fits vertical (Z-axis) precision stages, robotic joints that must hold position accurately without drifting, semiconductor and optical handling equipment, and other applications where both positioning accuracy and fail-safe holding matter on the same axis.
Why Choose the AW42HS Precision Gearbox & Brake Series
Combining a precision planetary gearbox with an integrated brake in one assembly saves the space and integration work of stacking a separate gearbox and brake unit, while still delivering ≤15 arcmin backlash and a shaft that locks whenever the motor is de-energized. NEMA 17 is the most widely supported stepper frame size in the motion-control ecosystem, and the square/round flange choice on the gearbox lets one motor selection drop into more mounting layouts without a redesign. For applications needing only the gearbox or only the brake, Apexwell's separate precision-gearbox and brake series on the same frame offer lower-cost alternatives. 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.
