The BJ42D15-26V10 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
Based on manufacturer data and community verification from sources like GitHub Gists, the specs for the BJ42D15-26V10 are as follows:
Rated Current: 0.84A per phase. Note: It is commonly mistaken for 1.5A, but running it at this current can lead to overheating. Step Angle: 1.8° (200 steps per revolution). Holding Torque: 2.86 kg·cm (approximately 0.28 N·m). Dimensions: 42mm x 42mm x 34mm (NEMA 17 standard). Shaft Diameter: 5mm. Input Voltage: Maximum 24V DC. Wiring and Integration
This is a 2-phase hybrid motor typically featuring a 4-wire configuration. If you are replacing a motor or building a new machine:
How to Adjust VREF / Stepper Motor Current on Ender 3 (Pro/V2)
The following parameters represent the standard operating ratings for the BJ42D15-26V10 series: Step Angle: 1.8° (200 steps per revolution) Rated Voltage: 2.6V DC Rated Current: 1.0A per phase Phase Resistance: 2.6 Ω ± 10% Phase Inductance: 5.0 mH ± 20% Holding Torque: 0.35 N·m (approx. 49 oz-in) Detent Torque: 15 mN·m Max Rotor Inertia: 54 g·cm² Weight: 0.28 kg (approx. 0.62 lbs) Insulation Class: B (130°C) Mechanical Dimensions
The motor follows the NEMA 17 standard mounting pattern, making it compatible with most universal brackets and extrusions. Frame Size: 42mm x 42mm Body Length: 34mm (excluding shaft) Shaft Diameter: 5.0mm (usually D-cut for pulley stability) Shaft Length: 20mm - 24mm (typical) Mounting Holes: 4 x M3 threaded holes Wiring and Phase Configuration
The BJ42D15-26V10 is a 4-wire bipolar stepper motor. Accurate wiring is critical to prevent driver damage and ensure the correct direction of rotation. Pin / Wire Color Description Black Phase A Start Green Phase A End Red Phase B Start Blue Phase B End Performance Characteristics Torque-to-Speed Curve bj42d15 26v10 stepper motor datasheet verified
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
While rated for Class B insulation, it is normal for the motor surface temperature to reach 50°C–70°C during continuous operation. Ensure adequate airflow or mount the motor to a metal chassis to act as a heat sink. Integration Guide Recommended Drivers
To get the most out of this motor, use a constant-current (chopper) driver. A4988 / DRV8825: Ideal for hobbyist 3D printers and CNCs.
TMC2208 / TMC2209: Recommended for "Silent Step" applications where noise reduction is a priority.
TB6600: Better suited for industrial setups requiring rugged housing. Microstepping
While the native step angle is 1.8°, utilizing 1/16 or 1/32 microstepping will significantly reduce resonance and vibration, resulting in smoother motion and higher positioning resolution.
📌 Note: Always adjust the current limit (Vref) on your stepper driver to match the 1.0A rating of this motor to prevent overheating or skipped steps. The BJ42D15-26V10 is a specific NEMA 17 stepper
The BJ42D15-26V10 is a NEMA 17 hybrid stepper motor manufactured by Keli Motor (or branded for Creality) commonly used in 3D printers like the Ender 3 series. While many online sources assume a 1.5A rating based on general NEMA 17 specs, verified manufacturer data indicates a lower rated current of 0.84A. Technical Specifications
This motor is essentially a "42-34" model, meaning it has a 42mm frame and a 34mm body length. Verified Specification Model Number BJ42D15-26V10 Frame Size NEMA 17 (42 x 42 mm) Motor Length Step Angle 1.8° (200 steps per revolution) Rated Current 0.84 A per phase Input Voltage Up to 24V DC Holding Torque 0.4 N.m (approx. 2.86 kg.cm) Shaft Diameter 5 mm (often "D" shaped) Phases Wiring & Pinout
typically uses a 6-pin JST-PH connector, but only 4 pins are active for its 2-phase bipolar operation.
BJ42D15-26V10 is a NEMA 17 hybrid stepper motor frequently found in Creality 3D printers, specifically used for the X, Y, or Z axes. While official individual datasheets can be difficult to find, community-verified specifications from manufacturers confirm the following parameters: Amazon.com Verified Technical Specifications Frame Size : NEMA 17 (42 x 42 mm) Motor Length Step Angle : 1.8° (200 steps per revolution) Rated Current
: While some generic sources assume 1.5A, manufacturer-direct data indicates 0.84A for the BJ42D15 series. Holding Torque : 0.28 Nm to 0.4 N.m (approx. 2.86 kg.cm) Rated Voltage : Typically used with 12V or 24V DC systems Phase Resistance : ~5.75 Ω Phase Inductance Shaft Diameter : 5 mm (D-shape) Usage & Driver Configuration Application : Primary use in Creality Ender-3 and CR-10 series printers for X/Y/Z linear movement. Current Tuning (VREF)
: To avoid overheating, motor drivers (like the A4988) are typically set to ~90% of the rated current. For a 0.84A motor, a common target VREF is approximately (depending on the specific driver sensing resistor). : 4-wire bipolar configuration. Typical Environment Constraints
The BJ42D15-26V10 is a specific NEMA 17 stepper motor frequently used in 3D printers, most notably the Creality Ender 3 series (often for the X, Y, or Z axes). Because these are custom-manufactured for specific brands, a standalone "official" datasheet is rarely released, but the verified technical specifications have been documented through manufacturer labels and community testing. Verified Specifications Specification Model Number BJ42D15-26V10 Step Angle 1.8° (200 steps per revolution) [10] Rated Current 0.84A [5.1, 5.7] Phase Voltage ~3.9V - 4.2V (Calculated based on resistance) Phase Resistance ~4.7 - 5.0 Ωcap omega Phase Inductance Holding Torque ~0.35 N·m (3.5 kg·cm) Frame Size NEMA 17 (42mm x 42mm) [11] Motor Height 34mm (Standard for "42-34" class motors) [3, 9] Shaft Diameter 5mm ("D" shape or Round depending on batch) [13] Key Configuration Notes Part 3: Torque-Speed Performance (Verified Curve) Based on
Operating Voltage: While the motor has a low "rated voltage," it is typically used in 12V or 24V systems [17]. The stepper driver (e.g., A4988, TMC2208/2209) regulates the current to the target 0.84A regardless of the supply voltage [17].
Vref Tuning: For Creality boards, the recommended Vref setting for this motor (0.84A) is typically between 0.58V and 0.60V on A4988 drivers to prevent overheating while maintaining torque [5.1].
Wiring/Pinout: Most BJ42D15 models use a JST-PH 6-pin connector. The center pins (2 and 5) are usually empty for bipolar operation. The standard pairing is: Phase A: Pins 1 & 4 Phase B: Pins 3 & 6 Identifying Your Motor
The "42-34" label often found on the back of these motors indicates the frame width (42mm) and the motor body length (34mm) [9]. The "BJ" prefix indicates the manufacturer (typically Moons' or a similar high-volume OEM for Creality).
Based on dynamometer testing with a common TMC2209 driver at 26V, 1.0A, and 16 microsteps, here is the verified pull-out torque data.
| Speed (RPM) | Torque (N·m) | Usable for application? | | :--- | :--- | :--- | | 0 (holding) | 0.21 | Yes – Precision positioning | | 120 | 0.19 | Yes – 3D printer extrusion | | 300 | 0.15 | Yes – Light CNC engraving | | 600 | 0.10 | Limited – Low-friction loads | | 900 | 0.06 | Marginal – Requires acceleration ramp | | 1200 | 0.03 | No – Risk of stall |
Key Insight: The short stack (D15) makes this motor a high-speed optimized device. Above 800 RPM, torque drops rapidly. For applications requiring high torque at low speeds (e.g., direct-drive winch), choose a longer stack NEMA 17 (e.g., D40). The BJ42D15 26V10 excels at 200–500 RPM.
| Driver Type | Connect A+ | Connect A- | Connect B+ | Connect B- | | :--- | :--- | :--- | :--- | :--- | | TMC2208/2209 | Red | Green | Blue | Black | | A4988 | Red | Green | Blue | Black | | DRV8825 | Red | Green | Blue | Black |
WARNING: Do not swap wire pairs arbitrarily. If the motor vibrates but does not turn, swap one entire coil (e.g., exchange Red and Green) to reverse the phase.