L298 Stepper Motor Driver - Back Voltage


In my project I'm controlling an EPSON printer motor. I'm using NANO circuit as my software platform using the L298 to drive the motor.

Noticed that Im not getting any improvment at the speed of the motor I found using my DVM that when I'm plug in the 12 Volt INPUT of the L298 driver to the source power it drops by Half Value.

The PCB contain all protection against BEMF or so, it's a familier one. Like in the great tutorial:


More ODD to me is that when I'm trying to work at higer voltage then 12 Volt, removing the 12 volt jumper the system stop working. no movment of the motor at all.

Hope some one can enlight me with wisdom about this issues. Thank you all.

Best Regards. Gabriel.

The antique L298 motor driver chip, despite claims by the manufacturers, is capable of providing only about 1 ampere per motor winding, and has an internal voltage drop of about 4 V at that current.

It is very likely that your motor would draw more current than the L298 can provide, but more information is required. Post a link to the motor product page or data sheet, or measure the winding resistance and tell us what it is.

In any case, you are much better off with a modern motor driver, like those from Pololu. https://www.pololu.com/category/120/stepper-motor-drivers

Is this a stepper motor or a DC motor?

There are lots of really bad L298N tutorials around. The Raspberry Pi Guy make one which has resulted in a bunch of dead R Pi boards.

The one you linked to looks okay but it still has errors.

I suggest trying the h-bridge without a microcontroller to begin with. Make sure the h-bridge can really source the current the motor needs.

After seeing the Raspberry Pi Guy's Pi killing tutorial, I decided to make a L298N tutorial myself. Here's a link to my version.

I'm not sure if I mention in the tutorial the need for low PWM frequencies. The L298N doesn't work well at high PWM frequencies.

If you jump to the end of my tutorial video, you can see a robot using two of those cheap L298N boards. As you can see from the video, the h-bridge does work. I used 200Hz as the PWM frequency.

I agree with jremington about the L298 not being a good h-bridge (I also say this in the video). It's just hard to resist these really cheap boards.

Edit: Sorry, I missed the "Stepper" part in the title.

Hello, Thank you all for your quick and proffesional responed.

I will do as you both suggested and reporet it back with conclusions.

The motor I am using is EM-546. Bipolar Stepper motor.

It a great toturial you made. Thank you very much.

Best Regards, Gabriel.

GabrielLevHar: The motor I am using is EM-546. Bipolar Stepper motor.

Sorry, I missed the "Stepper" in the title.

The cheap L298 boards can drive DC motors okay but I've had really bad luck trying to drive stepper motors with them.

I agree even more, now that I see you're using a stepper, with jremington's suggestion of using a different driver.