Stepper motor vibrates but does not turn.

Other Hardware Motors, Mechanics, Power and CNC
1

Hello,

I'm brand new to all of this so please be kind :slight_smile:

I followed this guide. Power is 6 volt 2 amp. Driver is an L298N.

I have tried reversing the coil leads on one, then the other, then both coils. Also tried reversing the order of the 8 9 10 11 pins as another guide had it that way. Have tried voltage from 3v to 9v. At 3v the L298N will not power. Other voltages had the same results.

In all cases the motor will vibrate in sync with the delay set in sketch, but will not turn. When energized the motor has strong resistance to manually rotating the rotor.

I am using the stepper_oneStepAtATime sketch from the library. The only changes made were to the delay and this line:
Stepper myStepper(stepsPerRevolution, 8, 10, 9, 11);
Although I also tried 8,9,10,11

Of interest: When I check voltage at the leads I get 6v, but checking it at the connecting screws shows 2v. I'm guessing thats the material of the screw, but also I can't power the arduino from the driver.

If by chance I have everything correct, how would I determine which components are faulty?

Thanks for joining my pity party :wink:

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2

The L298 will drop 2 to 4 volts, so even if the power supply can supply 6V the motor will only see 4V at best. The L298 is ancient and very inefficient technology and not suitable for modern low resistance bipolar steppers. I suggest that you get a proper modern stepper driver like the A4988 or DRV8825.

3

Hi,

First, WHAT motor?? What are it's specifications? How many wires??

Usually vibrate-not-step is a connection issue.

4

John, in the right side of the photo is shown the data plate of the motor.

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5

2.5ohm coils (image post#0) tells me that an L298 can't be used.
Need at least a 12volt supply, and a modern stepper driver board set to <=1.3Amp.
Leo..

6

Thanks so much! I have much to learn.

It appears we have consensus so I will order one of those drivers and report back.

For future reference I would like to know how you determined that the 2.5ohm would not work with the 298. I could find nothing in the 298 data sheets referencing resistance. Is this a calculation?

Again thanks for helping.

7

A 6volt supply into a 2.5ohm motor winding would be 6/2.5= 2.4Amp.
Absolute max coil current is 1.3Amp, so the motor could burn out.
Fortunately the L298 is an old lossy dinosaur with an average volt drop of ~2.5volt@1Amp in H-bridge mode.

If you use a constant current motor driver instead of a constant voltage driver,
then you can set motor current to a constant/safe value.
Then you also can use a higher supply voltage, to compensate for the current drop at higher motor speeds.
Leo..

8

These links may help
Stepper Motor Basics
Simple Stepper Code

...R