Stepper stalling when not connected to Arduino

Hi guys, I'm trying to build my CNC, but I'm having some issues... I'm using 42BYGHM809 stepper motors with 0.9 deg/step and I'm controlling them with an easydriver (last version)... I'm powering the board with a 24V 0.4A adapter, and as soon as I plug in the board, the motor (with no commands from the arduino) starts to nervously vibrate back and forward... I tried to change the power supply, using a 12V 0.35A adapter, but it still vibrates... When I apply my command, nothing seems to happen, it just keeps vibrating...
What is happening? :astonished:

Thanks for your help :slight_smile:

I did a search for the motor and found this: Good Quality! Wantai Nema 17 stepper motor 42BYGHM809 0.9degree 56oz-in 1.7A . Note the 1.7A. That could be 1.7 amps per winding . 0.4 amp supply might not cut it.

You probably need a 24v power supply that can provide about 4 amps per motor.

As far as I know you would need a BigEasyDriver for that motor and even then you would probably be at risk of overloading it unless you deliberately set the max current below what the motor can accept.

...R

http://www.aliexpress.com/store/product/High-Quality-Wantai-Nema-17-stepper-motor-42BYGHM809-0-9degree-56oz-in-1-7A-CE-ROHS/518269_1452264598.html

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Ok you guys are right, that's the problem... the Easydriver outputs 700mA whereas I need 1.7A/phase... What can I use to drive them then? Do I have other reliable choices apart from the Big easydriver?

Do I have other reliable choices apart from the Big easydriver?

What's wrong with the Big Easy Driver ?

At low speeds you won't draw much current from the 24V supply, 0.4A may be enough, but its too low
for fast operation. The driver acts as a buck regulator.

The vibration may mean you've connected something wrong - like the motor windings.

Never disconnect/connect stepper motor windings from/to a live stepper driver, always power
down first (otherwise its likely you'll blow up the driver).