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Overheating stepper shield

Hi Everyone,

As I'm a newbie, please forgive my ignorance for asking what maybe an obvious question. 

I've got an Arduino Uno and a DK Electronics v1.0 motor shield (powered separately at 12v). I downloaded a library and managed to get a NEMA 23 stepper motor working. Trouble is, the chip on the shield doing all the work gets scarily hot in next to no time. The rated current of the motor is 1A, although when I tried it, it was under no load. I've checked the power consumption when driving the motor from a standalone controller and it's drawing no more than 250mA.

Do you guys think:-

a) I'm overloading the shield?

b) I've got a fault?

c) I scare too easily?

Any feedback will be gratefully received.

Thanks

If you use a shield overheating can be "programmed" ;)

I had similar issues with a smaller motor and it turned out to be the progam at fault.

A little change and the motor still worked fine but without the electronics keeping everything under full holding power.

Also check the rating of the shield, some are just to be used for little motors and minimal loads.

With a seperate power supply, what is the motor drawing from it? If it is much more than in your standalone tests you should check the program.

Does it get hot without the motor connected ?

That board isn't very good. There are no current limits built in, so its perfectly possible you're pulling too much current on the motor. What is the winding resistance of it ?

Just put a heat sync on it.