6V and 12V stepper motors?
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I am working on a printer build that would require having 12V X Y and Z stepper motors, but 6V for both of the extruders. Is it possible to decrease the output voltage of the onboard drivers for just two of them, while leaving the rest alone? If not, any suggestions on how to do it?
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The way these sorts of stepper drivers work is they are current rather than voltage controlled so the voltage rating of the driver is not particularity important from the point of veiw matching VIN to the stepper.
Have a look here:
https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors
These sound like they are significnalty higher resistance than you would want for best performance:
Resistance and rated voltage
These are simply the resistance per phase, and the voltage drop across each phase when the motor is stationary and the phase is passing its rated current (which is the produce of the resistance and the rated current). These are unimportant, except that the rated voltage should be well below the power supply voltage to the stepper drivers. -
I am working on a printer build that would require having 12V X Y and Z stepper motors, but 6V for both of the extruders. Is it possible to decrease the output voltage of the onboard drivers for just two of them, while leaving the rest alone? If not, any suggestions on how to do it?
Stepper motor voltage is a very slippery concept. The drivers control CURRENT. I have motors "rated at 4v" running on 75V on big CNC machines. For years. Thousands of cuts.
Pick them according to Duet's (Dave's) guidelines here: https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors
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The general recommendations in the link says to "Avoid motors with rated voltage (or product of rated current and phase resistance) > 4V or inductance > 4mH."
What if I want this motor that is rated 6.5V, and 5mH? Will it have a big loss of torque or what is so bad about it? My power supply is 24V btw.
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Use the calculator at http://reprapfirmware.org/ to find the speed at which motor torque will start to fall.
