# Cooling A 500w Mini Mill Motor



## petcnc (Mar 23, 2016)

A few years ago I bought a Sieg X2 solid column Hi-power mini mill. It worked flawlessly for the small things I needed to make.








As I always seek better functionality I converted it to CNC, (full story here) a process quite difficult as I needed to solve too many problems.





Before the conversion I remember using the mill for hours without having any overheat issue. I suspect that I was worn out long before the mill! After the conversion I assign it the big job (for it’s work envelope) to make a 10X10 cm (4”X4”)  “turner’s cube”.






The cube was designed (CAD & CAM) in Fusion 360 and the g-code for it produced according to my machine’s Mach3 settings.

Although the cube is aluminum the poor thing has a considerable work to do some 3 hours per side!!!!

When machining started I noticed after an hour that the motor, working at full speed stated getting hot. At 2 hours I could not hold it for more than a few seconds with my hand. So I stopped machining and sought a solution to the new problem.

I had some old PC coolers (pentium4 type) that are designed to cool sufficiently a processor that produces 150Watt heating. As my motor is 500W I thought 2 of them at opposite sides will provide the cooling power needed.






After threading two rods, drilling some aluminum bars and some drops of thermal paste at conducting sides my motor stands proud and cool.






Job done (I thought), air will circulate through the fins and the motor will be cool as it should so lets go back to CNC machining…

After another hour I discovered that the circulation of the air was doing nothing! I had a hot motor and two hot coolers attached to it.

Aha! That’s the reason they attach a fan to the cooler!

Machining stopped again and the system upgraded with two fans.






Well, not any kind of fans but (from older computers) 2 noisy 12 volt DC fans.

Looking to old computer parts I also discovered a small thermostat (salvaged from an old computer PSU) that is designed to keep fan revs low when the PSU is cool and rev it up when it gets hot. Exactly what I needed! The thermo is bolted directly on the motor and adjusts the revs of the 2 fans automatically.






A switch that switches the circuit on (continuously), off and on through thermostat was also added.






System ready to work.






After 3 hours of machining  the motor is just warm to the touch.

I can say now "JOB DONE" loudly.



Thanks for reading.


Petros


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## JimDawson (Mar 24, 2016)

Great solution!  I like it!


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## ch2co (Mar 24, 2016)

Pretty cool!


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