Motor
NEMA17 Stepper Motor
Standard high-torque stepper used in 3D printers and CNC machines.
The industry-standard stepper motor size for 3D printers, CNC routers, and precision positioning rigs, typically driven via A4988/DRV8825.
Specifications
| Step angle | 1.8° per full step — 200 steps/revolution (microstepping via driver goes much finer, e.g. 3200 steps/rev at 1/16) |
| Holding torque | ~40-59 N·cm depending on model — check your specific motor's datasheet, this varies a lot between NEMA17 variants |
| Rated current | ~1.2A-1.7A per phase, model-dependent |
| Winding type | Bipolar, 4-wire (two coil pairs — not compatible with unipolar 5/6-wire driver wiring) |
| Typical driver | A4988 or DRV8825, needing a separate 8V-35V motor supply plus 3.3V-5V logic |
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | A+ | Coil A, lead 1 — to driver 1A/1B terminal (order within the pair can be swapped to reverse that coil's direction) |
| 2 | A- | Coil A, lead 2 |
| 3 | B+ | Coil B, lead 1 — to driver 2A/2B terminal |
| 4 | B- | Coil B, lead 2 |
These 4 wires go to the motor driver board (A4988/DRV8825), not directly to the MCU. STEP and DIR on the driver are what the MCU actually controls — set current limit via the driver's trim pot before first run, or the motor will overheat.