user32423: I am trying to control a Nema 17 motor with a L298n dual bridge and an Arduino Mega.
My wiring is from this Instructable:
http://www.instructables.com/id/Control-DC-and-stepper-motors-with-L298N-Dual-Moto/?ALLSTEPS
When I connect it to my laboratory power supply the current limitation blinks. Normally when there is too much current needed the LED is all the time on and not blinking. 
So I increase the current limit and the motor just starts moving on 3.1A @ 12V (doesn't move if less current) and in the description of the motor on amazon 
they say "Rated Current/Phase:1.2A" so I am wondering what did I do wrong here? 
From my understanding "Rated Current/Phase:1.2A" means that I should run this motor (it's a bipolar stepper motor with 2 phases) not higher than 2.4A? 
These are the informations from amazon about this motor:
Specifications: 

Led screw diameter: 8mm 
Lead screw length: 300mm 
Step angle :1.8 degree 
Nut material: Brass 
Holding Torque: 400mN*m 
Thrust(full step): 12.5kg 
Rated Current/Phase:1.2A 
Rate Voltage: 3.3v 
Rated Resistance/Phase:2.2±10%ohm 

What would be a good voltage to run this motor? I thought 12V is a good idea with.
The motor L298n gets really hot when I run it at 3.2A or more so I think my setup will destroy the dual bridge and / or the motor.
I really appreciate help on this! :-) 


user30676: The stepper motor does not directly control or limit its own current.  When using the L298n for stepper control, the motor current control is performed by a PWM signal to the L298n ENABLE pin.  If you have ENABLE high (100% duty), current will be a factor of only the DC resistance of the stepper winding and the power supply voltage.  Here you are trying to drive a 1.2A@3.3V-rated stepper from 12V, so naturally the current will be ~3 times greater.
To adjust the motor current to a safe range for the driver, use analogWrite() from a PWM-capable pin on the Arduino connected to the ENABLE pin on the L298n, and set it to something less than 255 (50% is usually a good starting point).  Even then, the instantaneous current draw on the L298n will likely be stressing it outside of its operating envelope.
EDIT: I reviewed the info at the link, and this is the relevant area of the code:
// set speed to 200 out of possible range 0~255
analogWrite(enA, 200);
// set speed to 200 out of possible range 0~255
analogWrite(enB, 200);

Here is where the code is setting PWM of the two ENABLE pins to 200 (~80% duty cycle).  Drop this to 50 (~20% duty cycle) and you would likely resolve your overcurrent issue.  Reading further still, even the author gives you your first hint at what is happening:

This is not a speed value, instead power is applied for 200/255 of an
  amount of time at once.


32423: <p>I am trying to control a Nema 17 motor with a L298n dual bridge and an Arduino Mega.</p>

<p>My wiring is from this Instructable:</p>

<p><a href="http://www.instructables.com/id/Control-DC-and-stepper-motors-with-L298N-Dual-Moto/?ALLSTEPS" rel="noreferrer">http://www.instructables.com/id/Control-DC-and-stepper-motors-with-L298N-Dual-Moto/?ALLSTEPS</a></p>

<p>When I connect it to my laboratory power supply the current limitation blinks. Normally when there is too much current needed the LED is all the time on and not blinking. </p>

<p>So I increase the current limit and the motor just starts moving on 3.1A @ 12V (doesn't move if less current) and in the description of the motor on amazon 
they say "Rated Current/Phase:1.2A" so I am wondering what did I do wrong here? </p>

<p>From my understanding "Rated Current/Phase:1.2A" means that I should run this motor (it's a bipolar stepper motor with 2 phases) not higher than 2.4A? </p>

<p>These are the informations from amazon about this motor:</p>

<p><strong>Specifications</strong>: </p>

<ul>
<li><p>Led screw diameter: 8mm </p></li>
<li><p>Lead screw length: 300mm </p></li>
<li><p>Step angle :1.8 degree </p></li>
<li><p>Nut material: Brass </p></li>
<li><p>Holding Torque: 400mN*m </p></li>
<li><p>Thrust(full step): 12.5kg </p></li>
<li><p>Rated Current/Phase:1.2A </p></li>
<li><p>Rate Voltage: 3.3v </p></li>
<li><p>Rated Resistance/Phase:2.2±10%ohm </p></li>
</ul>

<p>What would be a good voltage to run this motor? I thought 12V is a good idea with.</p>

<p>The motor L298n gets really hot when I run it at 3.2A or more so I think my setup will destroy the dual bridge and / or the motor.</p>

<p>I really appreciate help on this! :-) </p>

<p><a href="https://i.stack.imgur.com/7Zo0d.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/7Zo0d.jpg" alt="Arduino Mega with L298n dual bridge, Nemi 17 stepper motor, Arduino Mega and QJ3005EIII"></a></p>
 30676: <p>The stepper motor does not directly control or limit its own current.  When using the L298n for stepper control, the motor current control is performed by a PWM signal to the L298n ENABLE pin.  If you have ENABLE high (100% duty), current will be a factor of only the DC resistance of the stepper winding and the power supply voltage.  Here you are trying to drive a 1.2A@3.3V-rated stepper from 12V, so naturally the current will be ~3 times greater.</p>

<p>To adjust the motor current to a safe range for the driver, use analogWrite() from a PWM-capable pin on the Arduino connected to the ENABLE pin on the L298n, and set it to something less than 255 (50% is usually a good starting point).  Even then, the instantaneous current draw on the L298n will likely be stressing it outside of its operating envelope.</p>

<p>EDIT: I reviewed the info at the link, and this is the relevant area of the code:</p>

<pre><code>// set speed to 200 out of possible range 0~255
analogWrite(enA, 200);
// set speed to 200 out of possible range 0~255
analogWrite(enB, 200);
</code></pre>

<p>Here is where the code is setting PWM of the two ENABLE pins to 200 (~80% duty cycle).  Drop this to 50 (~20% duty cycle) and you would likely resolve your overcurrent issue.  Reading further still, even the author gives you your first hint at what is happening:</p>

<blockquote>
  <p>This is not a speed value, instead power is applied for 200/255 of an
  amount of time at once.</p>
</blockquote>
