stepper nema 17 + a4988 pololu stepper driver didnt rotate as well

Hi guys please help me… i tried to buid my first project Arduino cnc
the tools which i used to make it’s Arduino Uno + arduino cnc shield V3, driver stepper a4899 Pololu(2A), and stepper nema 17 12Vdc 1.8A…then i used GRBL for controlling…it’s work … but that mechine i made didnt rotate as well…power suply i used 12volt 1200mA(1.2A)…can you help me to resolve this cases…whats trouble??

Neither your power supply nor the A4988 driver supports 1.8 amperes/winding.

Carefully follow the directions on the Pololu A4988 product page to set the driver winding current to 1 ampere/phase or less, and use a motor power supply capable of providing more than 1.5 amperes. The higher the voltage, the better (within the A4988 limitations).

Hi thanks for the answer
and can you give me the resolution of my trouble…
and these are the components i used

Carefully follow the directions on the Pololu A4988 product page to set the driver winding current to 1 ampere/phase or less, and use a motor power supply capable of providing more than 1.5 amperes.

Post a link to the datasheet for your stepper motors.
Without that you are expecting us to fly blind.

You may find some useful info in stepper motor basics.


this is datasheet my motors u can check it below :

I have the same motors and they work fine with my A4988s.

Make sure you have the current limit properly adjusted on your A4988s. They only need 0.33amps. The Pololu A4988 web page has all the info you will need.

I drive mine with a 20v laptop power supply - but they should move with 12v.

If you have a breadboard you could mount one of the A4988s on it and wire it up as in the Pololu web page. This simple stepper code should work.


most people will tell you to use higher voltage to drive your motor without having a clue why.

from watching the posts of jremington, I believe he knows much more about steppers, so he would offer this from a point of understanding.

also, most people, and sellers do not understand steppers very well and how critical the motor voltage is in motor selection.

the motor voltage only explains the number of windings on the motor, it also tells you the maximum direct wiring you can do based on wire size and windings. however, motor drivers pulse power and you can drive a LOT more voltage into a motor.

what you are looking at is the RATIO of motor nameplate voltage to power supply voltage.
if you have a 1.2v motor and drive it with 1.2 volts, or a 5v motor and drive it with 5v, or a 12v motor and drive it with 12 volts, rated torque being the same, you will get the same performance out of each motor.

however, The motor’s output power is proportional to the power supply voltage divided by the square root of the motor inductance.

if you apply higher voltage, you can charge the coil faster and the motor comes to position faster, the motor has more power.

very generally, the higher RATIO of motor nameplate voltage to power supply voltage means more power from your motor.

if you have a 3v motor and a 12 v motor, rated for the same power, and then run the 3v motor on 12 volts, it would be the same as running the 12v motor on 48 volts. this is sloppy as it does not allow for inductance which will alter the results of the formula.

but when selecting a motor, either get the largest motor you can, or get a smaller motor with the lowest nameplate voltage you can.

personally, I think anyone selling steppers should not allow you to buy them without you understanding some of the basics.

can you explain "didn't rotate as well" ?

just what problem are you having ?

more on motor voltage

higher voltage will increase motor power at the cost of increased heat of the motor. the heat rises faster than the power, so the motor will get much hotter as you increase the voltage RATIO over nameplate. heat can become the limiting factor.
if you cannot get enough power with higher voltage and your motor gets too hot, get a higher torque motor.

whatever you do DO NOT run more amps. that will make the motor reach power faster, but it will also fake out the driver and the driver will not operate properly and the motor will overheat as you are driving the coils into saturation without the benefit of additional power.