17BB-H132-11 Stepper Warm to the Touch

DavidZemon

I just got my stepper motor working. Plugged it into a TB6612FNG and a 12V wall wart for power. Been spinning it like crazy on my desk, reveling in my new accomplishment. However, I just noticed it's quite warm. Not "oh I just burned myself" warm, but too warm for me to just hold comfortably. From what I gather, this is normal. I am, afterall, running current through it constantly. What I don't know is whether or not I should worry about it overheating. I don't have any load on it yet, just toying around with it free-spinning on my desk. Any concerns?

Phil Pilgrim (PhiPi)

Warm steppers are usually nothing to be concerned about. But, just to be sure, what's the winding resistance and current rating of the stepper?

-Phil

Peter Jakacki

Once the motor is up to speed you can drop the current but in the case of this chip it happens to be fixed but I noticed it had PWM input so maybe if you apply a little PWM at a suitable frequency you can reduce power consumption.

DavidZemon

Haven't found a current rating. Sticker on the motor says 75 ohms and 12V.

Phil Pilgrim (PhiPi)

Okay, that would imply 160 mA, or 1.92 W per winding. With two windings dissipating power at the same time, that would amount to about 4W. So, yeah, it's gonna get a little warm. 'Nothing to worry about.

But Peter is right: you don't need maximum input current if the motor is holding a position or up to speed -- unless there's an opposing torque.

-Phil