How to Select Stepper Motors
Info from Duet -
https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors
- It has notes about wiring steppers in series.
- "Avoid motors with rated voltage (or product of rated current and phase resistance) > 4V or inductance > 4mH."
- Shows how to identify stepper motor phases by shorting phases via wire
- Shows how to calculate maximum RPM before torque dropoff based on inductance
- Shows how to calculate back EMF due to rotation
- Shows how to calculate back EMP due to inductance
- Preferably, the driver supply voltage should be at least the sum of these two back emfs, plus a few more volts. If you have two motors in series then the required voltage is doubled.
- Example: a 1.8deg/step (i.e. 200 steps/rev) motor with 4mH inductance run at 1.5A using a 12V supply, and driving a GT2 belt with 20 tooth pulley would start losing torque at about 250mm/sec.
