Stepper Motor Options

In our application we try to find the sweet spot for good torque and high speed. The maximum speed of a stepper motor is determined by the following formula*:

$${Rev\over Sec} = {V\over{L*2*I_{max}*steps/rev}}$$

https://daycounter.com/Calculators/Stepper-Motor-Calculator.phtml

So we can see that the faster we want our stepper motors to turn, the higher voltage we need to have in our power supply. This value is restricted by the amount of voltage our driver can handle.

On the other hand, maximum current is inversely proportional to the maximum speed. At the same time, it is directly proportional to the torque. You see, this is an engineering trade-off between torque and speed.

This person explains how big stepper motors can be chosen.

We need to choose a power supply that can provide 2 times the amount of rated current of our motor. So for 4 NEMA 17 motors with 1.68 A of rated current, we need to have a power supply of 13.44 A or more.

According to A4988 datasheet, the maximum total current that can be drawn by 2 phases is 1.414*I_max. This gives us, with 1.68A for Imax, a total of 9.502 A for 4 motors.