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Author Topic: Official Arduino Motor Shield overheating.  (Read 313 times)
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So I have my Arduino Uno hooked up to my Motor Shield to drive a single 42HS4013A4  1.3A motor.
I have a good working code running exactly how I want, and am running a small 12v 12ah battery directly to the motor shield and have cut the VIN CONNECT jumper on the bottom of the shield.
However, within about 20 seconds of running, the shield chips get very hot and I disconnect power before thermal shutdown.

Am I doing something wrong or is this motor shield not capable of driving a 1.3A motor?  I don't care about speed at all, just need torque to open a valve.

Any tips or suggestions? 
Thanks so much,
Sean
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Yes, the page for the Arduino motor shield is just wrong - it claims 2A as the current
limit - which is only true if you water-cool the L298 (or put a large fan and heatsink
on it, which you can't since the heatslug is under the chip).

Even at 1A continuous each channel will contribute about 2.5W heating, so
2 motors at 1A each means 5W to the chip, well beyond its heat dissipation
ability on that board.

At 2A each channel would contribute about 20W of heating!
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Is there perhaps a way to lower the current draw from the motor and make it work, just weaker? 
If not, what would be a good alternative shield or controller for this specific motor?
Thanks for the quick reply, I'm surprised there aren't more youtube videos out there with nema17 motors controlled by Arduinos.
There are a couple, but nothing specifying the best setup for these motors.
Maybe I'll have to make one when this project is complete. smiley-wink
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There are hundreds, if not thousands, of posts on these and other forums from people discovering how poorly the L293 and L298 stepper drivers work with moderate to high current steppers, so it would be a service if you could correct the misinformation that has been spread about.

For your motor, the chopper drivers offered by Pololu should work well, A4988 or DRV8825. They offer a number of advantages, like microstepping and adjustable current control as well. http://www.pololu.com/category/120/stepper-motor-drivers
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Regarding motor current this is an interesting article. http://homepage.cs.uiowa.edu/~jones/step/current.html
Personally I would suggest just reducing the voltage.
Also helps with a stick-on heat sink to the L298 - but not much.
You could also drive the L298 with a pulse width mod output and maybe a 10:1 width which will give you 1 tenth of the current.

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