Stepper Motors - Chinstrap777/Chinstrap_3DP_Reference GitHub Wiki

Stepper Motor Terminology:

Step Angle: How much of a 360deg circle each full step completes.

  • 1.8 deg/step motors take 200 full steps to complete a revolution. Motors with bigger deg/step values allow for more speed at the cost of accuracy.

  • 0.9 deg/step motors take 400 complete steps. Motors with smaller deg/step values allow for more precise motion.

Voltage: the reference voltage required to make maximum current with the indicated resistance. With chopping stepper drivers used in nearly all 3d printers, this isn’t relevant. Additionally, higher voltages may cause more heating of the motors.

Current: Maximum recommended continuous (RMS) current per coil

Resistance: Rated resistance per coil

Inductance: Rated resistance to change in current

  • A higher inductance means the stepper driver will need to work harder to change direction/speed. Lower the inductance, the faster the motor can react (faster acceleration/jerk) as well as reduce EMF to allow for greater maximum speeds. Increased voltages can help overcome higher inductance, therefore increasing acceleration and speed, but will increase heating of the motors.

Holding Torque: Maximum torque motor can exert while powered. Higher is better.

Detent Torque: Torque when the motor is not energized.

# of leads: Quantity of wires you need to connect to run the motor.

Weight: lower is better if motors are on moving axis.

Winding Temp: Maximum temperature motor windings can sustain before damage.

Stepper motor identification

NEMA 14 = 1.4 inch diameter faceplate (most common for extruder motors on direct drive)

NEMA 17 = 1.7 inch (42mm) diameter faceplate (most common for axis motors on consumer grade 3D printers)

NEMA 23 = 2.3 inch diameter faceplate

LDO naming convention - example 42STH48-2504AC =

  • "42" mm mounting plate (NEMA 17)
  • "STH" Stepper- Hybrid
  • "48mm" body length (may be 60mm also)
  • "2.5" Amp rating (RMS)
  • "A" 1.8 degree/step (MA denotes 0.9 degree/step)
  • "C" regular temp 80-130C (H denotes high temp 180C)

Stepperonline naming convention - example

List of popular stepper motors.

NEMA 14

NEMA 17

LDO

LDO 42STH48-2504 SERIES - 2.5A

LDO 42STH48-2504AC - 2.5A rating, 24mm D-shaft, 1.8 deg/step data sheet / torque curve

LDO 42STH48-2504MAC - 2.5A rating, 24mm D-shaft, 0.9 deg/step data sheet / torque curve
LDO 42STH48-2504AH - 2.5A rating, 24mm D-shaft, 1.8 deg/step, high temp
LDO 42STH48-2504AC(S46) - 2.5A rating, 46mm D-shaft, 1.8 deg/step data sheet / torque curve
LDO 42STH48-2504MAC(S46) - 2.5A rating, 46mm D-shaft, 0.9 deg/step data sheet / torque curve
LDO 42STH48-2504AC(S55)
LDO 42STH48-2504MAC
LDO 42STH48-2504MAC(S55)
LDO 42STH48-2804 SERIES - 2.8A
LDO 42STH48-2804AC - 2.8A rating, 24mm D-shaft, 1.8 deg/step data sheet
LDO 42STH48-2804AC-R - 2.8A rating, 24mm round shaft, 1.8 deg/step data sheet
LDO 42STH48-2804AH - 2.8A rating, 24mm D-shaft, 1.8 deg/step, high temp data sheet
LDO 42STH48-2804AH(S55) - 2.8A rating, 55mm D-shaft, 1.8 deg/step, high temp data sheet

Stepperonline (OMC)

NEMA 21