Stepper Motor Heat

So…I have the machine assembled with all axis moving freely. I am an old school Mach3 guy. In doing some preliminary testing this evening with my steppers I have a lot of heat on the motors. For my other CNC builds that use wood or aluminum the stepper heat wasn’t a concern. And for those machines having hot motors was pretty typical. For PLA mounts the heat bothers me. I put a thermometer on the motors and after about 10 minutes the temp was around 110F.

I would imagine that the Ramps set up runs much cooler, but having never played with that arrangement I don’t know.

So how hot are the steppers on other people’s builds?


What kind of current are you sending them? I think most newma 17s are set to handle 50C over ambient.

Mine get slightly warm, if I can not keep my hand on them I turn down the juice. I have no idea how much power I might be leaving on the table but I have never really had a power issue that I know of.

Thanks for the reply. I’m actually not sure how much power is heading to the motors; I’m using a control box that was on an old 3040 CNC. The board is a JP382A, just an inexpensive Chinese board. I’ll have to see if there are some dip switches I can play with to drop it down a touch.

I really like the simplicity of the Ramps set up, and hope to play with it someday, however having all of the control from Mach is very nice.


The control should really not be very different. When you get to try the other stuff it should not be very different.

You should verify the power output soon. You can damage your steppers running them too hot. It is actually a pretty precise measurement when you get near the limit. one cut running to long and you might lose a stepper.

Pla gets pretty soft at 60C.

Roger that. Thanks. I opened up the box with the JP382A board and there are no dip switches; it looks like the thing is set to go full power all the time. So, that won’t work here. The motors are far too warm. I have a different controller here that does have switches an I can drop it down to 25% so I’ll check that out this evening I hope. If that still runs too hot I’ll buy your Ramps set up and go from there. It’s all a learning experience, that’s the whole point of all this. If I order the set up from you this evening could it be here by the weekend? I’m in Maryland.


Bummer, there is no config file or something you can change? Some of the reprap board have digipots and the current is set in the software. That would suck to have to replace something you already have.

Found some time this evening to tinker. My old Toshiba 6560 controller has dip switches and when I drop the current down to 25% the motors stay comfortable. Just slightly warm to the touch. I let them sit idle for close to an hour and they were just warm so I think we’re okay there. I also tested the drivers on the Toshiba board with doubling up with two stepper on one driver and after playing with the speeds and decay settings all seems good. These NEMA 17s were advertised as high torque (76oz) motors and they really have some strength.

So far I have the Z motor wired and pulling strong. I bumped it up to 125ipm and it did great. I’m using Mach3 on an old laptop with a UC100 controller. Hope to get more of the motors wired up by the end of the week. I also ordered a 500 watt spindle primarily for the noise control. I had a spindle a while back and boy are they nice. The 500 watt unit should work for most of the projects I do. If I really need some serious muscle I could switch it out and drop in a DeWalt pretty easily.


Serious problems with that setup…Entirely too clean. Stop making things tidy and start getting them dirty!

Good to hear you should be up and running soon with some upcycled components.

Ha. Yeah, the wiring is clean but the rest of my shop is an absolute disaster. Slowly making progress this week. Hope to get another video up by the end of the weekend.