First time stepper motor attempt and rising smoke

Other Hardware Motors, Mechanics, Power and CNC
1

Hello,
I am trying to get a small Nema 17, 2a stepper motor to work. I've followed this comprehensive guide. I'm using the 8825 driver and a 24v 3A power supply.

Unfortunately when I plug in the power to attempt the current limiting part I get some kind of short and something fries - puff of smoke from the driver on the breadboard. I'm not sure where to troubleshoot at all. I repeated it with all new components and making sure connections were correct but got the same result.

I'm also curious if setting the current limit is even needed as the driver maxes at 1.5 and the motor at 2A.

Any help would be appreciated as I'm a beginner here.

2

Then you weren't actually following that guide, which is for an A4988 motor driver.

I'm also curious if setting the current limit is even needed

Setting the current limit is absolutely required, and it must be set to less than the rated maximum current for the motor driver.

3

The guide covers 2 drivers and yes it includes the 8825.

What am I missing with setting the current then and how would you do it without the power supply connected? Like I said, it fries basiclly once power is connected.

4

What did you do to set the current limit?

Never change wiring when devices are powered. If you did so, then that was probably what fried the motor driver.

Also, breadboards, which are designed for temporary experiments with low power logic devices, cannot be used for motor currents. The tracks will burn, and that can also lead to fried motor drivers.

5

Ok Thank you.
Figured out my initial problem.. embarrassingly had the driver upside down. Let's pretend that did not happen..

Ok now I'm getting very, very low, if any Vref when adjusting the pot. (new driver)

6

We have all made those mistakes, many times.

If you are using a breadboard, the tracks may have been burned by the last mishap, and it should probably be discarded.

It is best to wire motor power and motor leads directly to the driver module, either using soldered pin headers, soldered wire connections or secure screw terminals if provided.

7

Better follow the Pololu guides.

Motor current is first set with the motor disconnected.
If you measure coil current (you shouldn't), then you could be 30% off.
Leo..

8

Hi again,
Despite a few other attempts I could not get the DRV8825 setup to work.
I went ahead and bought one of the L298N driver boards.
The motor turns (horray!) but now I'm having overheating issues on the driver. Please set me straight.. The motor is rated at 2amp, and phase resistance of 1.8 ohm's.
Seems my power supply would be quite low voltage like 4v then for this to work well?

I fried my first driver using a 24v 3 amp power supply, then tried a 12v 6amp and that got hot to where function was effected and I think would have eventually fried as well.

9

The ancient, extremely inefficient L298 can handle only 1 Ampere per channel, continuously, and wastes a huge amount of power (with an internal voltage drop of as much as 4V).

The L298 is primarily for low power brushed DC motors (toys) and not at all suitable for low resistance stepper motors. Use a current limiting driver for those.

10

Congratulations and welcome to probably the biggest electronics group around. Probably all of us are members.