VREF=Itarget×8×Rsense=0.714×8×0.10≈0.57 Vcap V sub cap R cap E cap F end-sub equals cap I sub target end-sub cross 8 cross cap R sub sense end-sub equals 0.714 cross 8 cross 0.10 is approximately equal to 0.57 V Step 3: Physical Tuning Adjustment
The is a specific NEMA 17 stepper motor frequently found in Creality 3D printers, such as the Ender 3 series. Finding a "verified" datasheet for this specific model has long been a challenge for the hobbyist community, often requiring direct contact with the manufacturer, Keli Motor Group . Verified Technical Specifications bj42d15 26v10 stepper motor datasheet verified
| Parameter | Value | Verification Method | |-----------|-------|----------------------| | Model | BJ42D15 26V10 | Label inspection | | Phase | 2 | Electrical continuity | | Step Angle | 1.8° ± 5% | Oscilloscope / encoder | | Number of Leads | 4 | Visual | | Rated Voltage | 26 V DC | Power supply test | | Rated Current per Phase | 1.0 A | Current probe | | Winding Resistance | 26 Ω ± 10% @ 20°C | 4-wire ohmmeter | | Winding Inductance | 28 mH ± 20% @ 1 kHz | LCR meter | | Holding Torque | 0.42 N·m (59.5 oz·in) | Torque sensor (at 1.0 A) | | Detent Torque | 0.022 N·m (3.1 oz·in) | Torque wrench method | | Rotor Inertia | 54 g·cm² (0.54 × 10⁻⁵ kg·m²) | Calculated from acceleration | | Mass | 0.35 kg (12.3 oz) | Precision scale | | Body Length | 39.5 mm (excluding shaft) | Digital caliper | | Shaft Diameter | 5 mm | Micrometer | | Shaft Length | 24 mm | Caliper | | Max Radial Load | 28 N (5 mm from face) | Static load test | | Max Axial Load | 10 N (push/pull) | Force gauge | | Insulation Class | Class B (130°C) | Thermal camera | | Dielectric Strength | 500 VAC for 1 minute | Hipot tester | | Insulation Resistance | >100 MΩ @ 500 VDC | Megohmmeter | VREF=Itarget×8×Rsense=0
While labels vary by manufacturer (KELI, Creality, or Elegoo), the standard bipolar wiring scheme is universally: As stepping frequency increases
At its rated 1.0A current, the BJ42D15-26V10 maintains a flat torque curve at lower RPMs. As stepping frequency increases, the inductive reactance causes a gradual drop in torque. Using a higher-voltage chopper driver (e.g., 12V or 24V) is recommended to overcome back-EMF and maintain performance at high speeds. Heat Dissipation
When replacing a BJ42D15-26V10 motor, ensure the replacement matches these specifications: