[ryansuperbee]

Hello. I have a Smithy 1240 CNC milling machine. Whenever I run a program for more than a half hour the stepper motors become hot to the touch. I have tried loosening the gibs as much as I think I can (maybe not enough though) to free up some of the load on the steppers, but that did not seem to work. Since then I use the air compressor every few minuets to keep the steppers at a decent temperture. Is there too much load on the steppers? or is there some product that I can buy to keep the steppers cool, even liquid cooled? I've been thinking about mounting a air conditioner under my milling machine and ducting the air to the steppers. Could this work? Or is it something beyond that? please advise

[kawazuki]

From what i've been reading in the Gecko threads, heat is generally the result of high voltage to the stepper and so is a side effect of fast speeds? 50 - 60 deg C is not uncommon with 85 deg C the highest i've seen quoted!
Seems bloody hot to me but i'm new to this so don't quote me!

[CROSSHATCH]

Heat is due too the amount of voltage your putting into the steppers and what they are rated for. Speeds do as well affect the temps.


-Jason

[jalessi]

Some stepper motor drivers have idle current reduction options.

You might want to contact the vendor you purchased your machine from and ask if your steppers drivers have this option.

If they do its a matter of flipping a dip switch or adding a jumper, and presto your stepppers will be running much cooler without effecting the motors performance ..

Most stepper drivers have this option.

Jeff...

[Teyber12]

you should measure the temperature, preferably with a thermocouple thermometer. "OMFG HOT" is usually around 45c- what i mean is when you touch something and your body screams hot. I think your just fine and really don't need to blow air over them. If your totally anal i guess you could mount some fans but i really don't see the need.

regards

[ryansuperbee]

Jeff, how does this work in cooling the motors? It sounds promissing.

[Teyber12]

Jeff, how does this work in cooling the motors? It sounds promissing.

Its in the controllers- please slap me if im wrong but it morphs the steppers from on to off when not being used to reduce heat output. its actually not a cooling system.

regards

[ryansuperbee]

Teyber, I don't have anything to measure the temperature of the motors, where would I get a thermocoulper thermometer? But for now, if I had to guess the hottest they have been is about 120 degrees F. Maybe hotter though. I know that as magnets get hotter they start to dramatically lose efficiency. Does that apply for steppers as well? Would cooling fans have an effect?

[jalessi]

The Idle current reduction capability is to save energy and to avoid unnecessary heat dissipation into the stepper motor

The stepper driver should have dip switches or jumpers to control this option.

What model stepper drivers do you have?

Jeff...

[ryansuperbee]

Jeff, I'm not sure what kind they are. The machine is a 1240 by Smithy. Hey here's an idea tell me what you think of it. If you go to google.com click images in the top right hand corner, and then type in "liquid cooled" scroll down to the 5th row of pictures on th left hand corner the electronics are submerged!!! I actually heard about this before. 3M makes a liquid that is made to be able to submerge electronics and use them! If you scroll thru a few more pictures you will see a complete computer system sumerged. Wouldn't something like that work with the steppers? You could even have it circulate. I'm nervous...

[jalessi]

This is directly from the Syil X3 manual

"Auto Half Current"


See attached jpg

Hope this helps,

Jeff...

[jalessi]

Ryan,

You have two choices, open the controller enclosure and do some investigation

or call Smithy in the a.m. and ask them to email you the setup instructions for your stepper motor drivers.

One of the experienced members here on the Zone will help you make the adjustment.

Jeff...

[jalessi]

Ryan

The stepper motor iron is permeable, the liquid would cause the motor to lose torque.

You could epoxy heat sinks on to the motors.

http://tinyurl.com/5fueph

http://tinyurl.com/6m7s29

Jeff...

[Robin Hewitt]

Load doesn't affect stepper current, much the same even if you stall it. Overly tight Gibbs = lost steps, not hot motors.

Hot could means you are flowing too much current, there are two current ratings for a 8 lead motor depending on whether you connect parallel or series.

If it was okay and you haven't changed anything and one motor is getting hot, perhaps one of the windings inside has cross-connected. Can you measure the coil resistances? Is one lower than the rest?

Do you have excessively long leads between controller and motor? Perhaps the controller is fighting an awkward resonance when it tries to control the current. Chopper circuits can get fretfull if the leads are long.

Milling machines make great heat sinks, you just have to provide a thermal path