FAQ About Stepping Motors and Power Supplies

We get a lot of questions about what stepper motors and CNC power supplies to use, so we've started this page. A lot of this information is scattered over the rest of the wiki, but it's nice to pull it together in one place.

FAQ About Stepping Motors and Power Supplies


General
NEMA17 versus NEMA23
TinyG is capable of delivering 2 amps per winding, and 2.5 amps per winding with cooling. Given that, we have never found a NEMA17 that would not work with TinyG, and almost every NEMA23 we have tried will work if rated up to about 3 amps per winding (with the caveat that you might not get full power if it calls for more than 2.5 amps). We also routinely run NEMA34's, but not at full power and therefore not in high mechanical load situations.

What's with the motor's rated voltage?
The question comes up - can I run a motor with a rated voltage of 4.2 volts (for example) with a 24 volt supply? Will this burn out the motor?

The motor's rated voltage is irrelevant and can be ignored. Any stepper motor rated at any voltage will work, regardless of the power supply voltage provided. The rated motor voltage just states what the max voltage would be if you applied a direct DC voltage to the winding and wanted to stay in the rated current of the motor. Since the stepper drivers regulate the current the voltage doesn’t matter.

In fact, the lower the rated voltage the better as this is a reflection of low impedance windings which will transfer power better and provide "snappier" operation than a similar motor with a higher voltage rating.

Finding the Coil Pairs on a stepper motor
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