Quote Originally Posted by Neale View Post
I was surprised at how hot steppers run - problem is that they need to draw power even when stationary to hold position. As said above, most stepper drivers have a "half-current" option that reduces current to half when the motor is stationary for more than a second or so, which reduces heating considerably. I aim to have my motors run at about "just not quite too hot to hold", which is around 60C.

I start with the nominal rated current of the motor, based on its spec, and set the driver accordingly. I then adjust the max current so that in normal use the motor ends up at about the temperature as mentioned. There's a lot of discussion around things like peak/average/RMS current and what the driver settings mean. These discussions usually end up with a general conclusion of "search me, Guv!" as no-one is quite sure what the driver and the motor manufacturers are specifying. Hence the rule of thumb, "adjust so it's at about the right temperature."
Hi Guys thanks for the replies. I ran the machine in idle this morning, the temp rose slowly over a 45 minute period, until it reach almost unholdable state, thats is as far as I got. The X motor which is smaller that the others got barely warm.
POwer supply is 36 volts, the drivers are DM542, the Motors are rated at 4.2 amps. I am almost sure I set them at halve current setting. I will open up the case and have a look.