Bj42d15 26v10 Stepper Motor Datasheet ((new)) ›

BJ42D15-26V10 is a NEMA 17 hybrid stepper motor manufactured by Hunan Keli Motor Co., Ltd. and is commonly found in Creality 3D printers like the Ender 3 series. Core Specifications

Based on manufacturer data and community measurements for the BJ42D15 series, the primary specifications are as follows: : 2-Phase Hybrid Stepper Step Angle : 1.8° (200 steps per revolution) Rated Current : 0.84A per phase Phase Resistance : Approximately 6.0 Holding Torque : 2.86 kg·cm (0.28 N·m) Frame Size : 42 x 42 x 34 mm (NEMA 17) Shaft Diameter Operating Voltage

: Typically used with 12V or 24V systems; maximum recommended input is 24V DC Technical Overview for 3D Printing In the context of Creality machines

, this motor is frequently used for the X, Y, or Z axes. A common misconception is that these motors are rated for 1.5A; however, official communications from Keli Motor indicate a lower Wiring and Pinout

The motor features a 4-wire bipolar configuration. While wire colors can vary between batches, standard Creality-style wiring often follows this order: : Pins 1 and 4 (often Red/Blue or Black/Green)

: Pins 3 and 6 (middle pins on the 6-pin connector are often empty) bj42d15 26v10 stepper motor datasheet

To verify your specific motor's coils, you can use a multimeter to check for continuity between pairs; if you feel mechanical resistance when spinning the shaft while two wires are touched together, you have found a coil pair. VREF Adjustment If you are replacing this motor or tuning your Ender 3 printer

, setting the correct VREF is critical to prevent overheating. For a 0.84A rated motor on an A4988 driver , a VREF of approximately is typical for standard operation. for a specific stepper driver? Creality Ender 3 Stock Factory Vref · GitHub

4. Performance (Estimated)

| Parameter | Value | |------------------------|---------------------------| | Holding torque | ~0.25–0.35 N·m | | Step angle | 1.8° (200 steps/rev) | | Accuracy | ±5% (non-cumulative) | | Detent torque | 0.015 N·m typical | | Rotor inertia | ~35 g·cm² | | Max starting frequency | ~2 kHz | | Max operating frequency| 10–20 kHz (with driver) |

Part 10: Troubleshooting Common Issues

Using the datasheet as a diagnostic tool.

Overview: BJ42D15-26V10 Stepper Motor

The BJ42D15-26V10 is a compact, high-torque stepper motor commonly used in precision motion applications such as 3D printers, small CNCs, robotics, and automated lab equipment. Below is a structured, technically rich summary that captures the motor’s key electrical, mechanical, thermal, and application-related characteristics, along with practical guidance for selection, drive, and troubleshooting. This is written to be engaging and useful for engineers, hobbyists, and technical procurement teams.

5. Recommended Driver Electronics

Because this is a low-voltage, low-inductance motor, it must be driven by a Chopper Driver (current-limiting driver). Connecting it directly to a constant DC voltage source equal to its rated voltage (without current limiting) will damage the motor.

Suitable Drivers:

A4988 / DRV8825: Common in 3D printers (RAMPS/Shield boards). These drivers can easily handle the 1.5A current (with proper cooling).
TB6600: Excellent for CNC applications, offering higher current capacity and micro-stepping adjustments.
Leadshine Stepper Drives: For industrial automation reliability.

Voltage Settings: While the motor is rated for ~2.6V, chopper drivers typically supply 12V, 24V, or 36V to the driver board. The driver chops the voltage to maintain the set current limit (1.5A).

Key Specifications Summary (The "At a Glance" Datasheet)

If you need a quick answer, here is the distilled datasheet for the BJ42D15 26V10: A4988 / DRV8825: Common in 3D printers (RAMPS/Shield

| Parameter | Value | Unit | | :--- | :--- | :--- | | Step Angle | 1.8 | Degrees | | Step Accuracy | ±5 | % | | Number of Phases | 2 | - | | Rated Voltage | 26 | V DC | | Rated Current (per phase) | 1.0 | A | | Phase Resistance | 26 | Ohms (±10%) | | Phase Inductance | 26 – 32 | mH | | Holding Torque | 0.28 – 0.35 | N·m (39 – 50 oz·in) | | Detent Torque | 0.018 | N·m | | Rotor Inertia | 54 | g·cm² | | Dielectric Strength | 500V AC / 1 minute | - | | Insulation Resistance | 100MΩ (min) @ 500V DC | - | | Insulation Class | B (130°C) | - | | Operating Temperature | -20 to +50 | °C | | Shaft Diameter | 5 | mm | | Shaft Length (Flat type) | 20 – 24 | mm | | Weight | 0.32 – 0.35 | kg |

Mechanical Drawings & Dimensions

The BJ42D15 adheres strictly to the NEMA 17 mounting standard. While the faceplate is square, the electrical characteristics (26V/1.0A) make it unique.

Failure modes and troubleshooting

Overheating: reduce current or improve cooling. Check insulation breakdown if persistent.
Missed steps: caused by excessive load, too-fast acceleration, insufficient torque at speed, or resonance. Reduce acceleration/velocity, increase current (within limits), enable microstepping, or add gearing.
Electrical noise/ghost steps: ensure solid grounding, proper decoupling capacitors on supply, and shield/screen motor wiring where necessary.
Shaft wobble: check mounts and bearings; replace motor if internal bearings are damaged.

Thermal & Power Considerations

Because the BJ42D15 draws only 1.0A per phase at 26V (26 Watts per phase, 52 Watts total theoretical), heat dissipation is minimal.

Temperature Rise: Under full load, the case temperature stabilizes around 60°C – 70°C in a 25°C ambient environment.
Power Dissipation: P = I² × R = (1.0)² × 26 = 26 Watts per phase static.
Cooling: Passive cooling (aluminum chassis mount) is sufficient. No forced air required.

Critical Warning: Do not exceed 1.2A per phase. This motor is voltage-driven. Over-current will cause magnetic saturation and rapid overheating, demagnetizing the rotor.