EasyDriver temperature

I am using an easydriver with a 0.3A motor using the sparkfun example. The motor moves fine back and forth, but the easydriver gets hot. I noticed that when I put my ear near the motor (with the motor in a stationary state) I hear a faint buzz. Is this normal? The motor is not hot, its the Easydriver.

The driver chip is designed to run a bit hotter than you can comfortably touch.

To what value did you set the current limit?

I am not aware that the easydriver current can be set. How do I do that?

All modern stepping motor drivers require you to set the current properly.

Consider using your favorite search engine, together with a phrase like "easydriver set current limit", to learn more.

sed003:
I am using an easydriver with a 0.3A motor using the sparkfun example. The motor moves fine back and forth, but the easydriver gets hot.

Warm or hot is normal, but if set for 0.3A I'd expect warm rather than hot - yet the motor isn't hot, so its
not too far from something sensible.

I noticed that when I put my ear near the motor (with the motor in a stationary state) I hear a faint buzz. Is this normal?

Absolutely, the controller is chopping the supply to regulate the current to each winding, which will lead
to some noises in the windings.

The motor is not hot, its the Easydriver.

I suspect you may have an inadequate supply voltage as your motor seems to be high-impedance.

Can you provide details of motor and supply?

The power supply is 12V 1.5A, The motor is SM-42BYG011-25 1.8deg, another motor is 17HS1352-P4130
I tried playing around with the potentiometer on the the easydriver and tried to get the readings as link below suggests. Since then I cannot change it to get the original resistance reading that I had before changing it. It used to be 8 ohm i believe, now between 4 and 5 regardless of where i set it. I am doing the measuring with the power off.

I am uncomfortable with leaving the power ON with a tiny board that gets that hot.

Without getting distracted from the topic at hand, in a similar application (curtain opener) I am using a bigger motor 2.5A with a TB6560 controller. It works like a charm and despite the large heat sink on it, it is cold all the time.

I am doing the measuring with the power off.

That won't work.

See Pololu's post showing how to set the current for their A4988 driver. The precise setting depends on the current sense resistor installed.

Without a fan and/or excellent heat sink, the A4988 cannot handle more than about 1 Ampere per winding.